Thursday, December 29, 2016

Defense Against Roundhouse Punches in Dan-Gun

Much of this post is derived from my previous post Chon-Ji Addendum: More on Basic Blocks. You may check that out for additional information.

In my previous posts on Chon-Ji, I gave two defenses against straight punches using movements from the form. For a straight punch, deflecting inward is ideal. A roundhouse punch -- also called a haymaker or windmill punch -- is a different matter. Your options are either to back away, duck, or to block while stepping inward. As you might imagine, Dan-Gun deals with the latter type of defense. A person stronger than you will put a lot of power into this punch, so how we block deserves some analysis.

In this post I've going to detail four roundhouse punch defenses from the form Dan-Gun, using elements of it you may not have considered, such as chambers and the footwork.

Option 1

This defense uses:
  • Back stance knifehand guarding block
  • Front stance high punch
  • Turn 90-degrees into front stance low block
You might be thinking that the application is to block with your front forearm (guarding block) before stepping in and punching the jaw (high punch). In reality, this is a terrible way to defend against a roundhouse punch. Your front forearm alone is not strong enough, and since the punch is round it'll just curve around it and smack your head. Instead, as I previously noted, the chamber for the guarding block serves well as a roundhouse punch defense.

Application for taekwondo knifehand gaurding block (various examples)
The block proper is used to simultaneously push out on the opponent's neck (front forearm) while overhooking their arm (back arm), as shown in the right most image above. The pushing prevents them from hitting you with their other arm.

Inside trip with hip bump
There are several follow-ups you may do from this position. You can use your front arm to elbow strike the opponent or press into their neck. In the form, we're going to take advantage of the circular footwork again. Instead of circling behind an opponent's legs for an outside trip -- like we did in Chon-Ji -- as we move into the front stance high punch we're going to circle around the opponent's front leg from the inside, setting up what's called an "inside trip" in wrestling and "o uchi gari" (major inner reap) in Judo. 

What's the high punch? Well, if you're controlling the opponent with your front forearm, they're probably resisting you. You're going to let them up and then punch across their jaw after you circle around their leg.

High punch followed by 90-degree low block
Now for the takedown: with your punching arm in front of your opponent's neck, you're going to move your front leg back (reaping out their leg) as you turn 90-degrees and push their head downwards with the low block. This takes them to the ground.

So the whole defense is:
  1. Block with both arms (guarding block chamber)
  2. Wrap the attacking arm while pressing on opponent's neck with front forearm (guarding block)
  3. Circle around opponent's front leg for an inside trip, then punch across their jaw (high punch)
  4. Reap out their leg as you turn 90-degrees and force their head downwards (low block)
Option 2

This defense uses:
  • Front stance high punch
  • Front stance high punch 
  • Step out with back leg, rotate 270-degrees into back stance twin outer-forearm block
Sometime you should keep in mind regarding forms is that the "double blocks" are not actually blocking two attacks at once, but rather are grappling motions. The twin outer-forearm block, for example, works well as a head-and-arm trap, something that Krav Maga instructors seem to like. (fnt. 1)

Use the setup arm for the first high punch as a parry. Step in and raise your elbow over your opponent's shoulder (first high punch) as you trap their arm (reaction hand pull to hip). The next trap requires minimally two steps: step forward again and raise opponent's arm as you push down on their head (second high punch), then step out with your back leg and rotate, still lifting the arm and maintaining pressure on the head (rotate 270-degrees into twin outer-forearm block).

From here you may do a number of follow-ups; knee strikes tend to be a favorite of Krav Maga practitioners. An inward strike to the neck (from Won-Hyo) is another. If you wish to follow the form, follow up with the same high punch followed by turning 90-degrees into low block takedown as before. (fnt. 2)

You might be wondering why you don't just punch their jaw immediately after using the setup arm to parry. You could do that! However, be warned that a frontal punch to the head risks breaking your hand, especially if the opponent tucks their chin in and you hit their cranium by accident. A better option is a high palm strike rather than a high punch.

Non-gif example
Option 3

This defense uses:
Rising block, using the reaction hand to trap
  • Front stance rising block
  • Front stance rising block
  • Step out and pivot 270-degrees 
The fact that we chamber our rising block on the inside makes the application fairly simple. We're going to block, trap, then block the opponent's other arm (using blocks as blocks; how novel!) However, the way we're going to block may seem unorthodox.

For the first rising block, rather than using the forearm to defend the top of our head, we're going to use the upper arm to defend the side of our head. This is quite similar to a defense from bare-knuckle boxing called the "winged hook", and it uses the same principle as the helmet guard from modern boxing: raising the elbow to defend the side of the head. But since bare-knuckle boxing and traditional martial arts use a long guard, it's more economical to just raise the elbow than to bring your hand all the way behind your head. (fnt. 3) This application may explain why some karate schools keep the rising block so close to the head.

(Left) Rising block, using the elbow to defend (Middle) "winged hook" from bareknuckle boxing (Right) helmet guard from modern boxing
After blocking, trap the arm (chamber for second rising block). Step in and use your forearm to block your opponent's other arm at the elbow or higher (second rising block). The rule I use to remember this is to always match forearm to upper arm. Now that you are pulling down one of your opponent's arms and raising their other arm, you have them in an unbalanced position. Step out with your back leg and pivot while still pulling them, creating a rudimentary throw.

This defense (helmet guard followed by uppercut), while not
the same moves, follows the same principle as two sequential
high blocks
As an alternative, the second rising block can be a forearm strike to the jaw. The benefit of using your forearm to strike is: 1) large surface area; very difficult to miss, 2) No risk of breaking any small hand bones as you would with an uppercut, and 3) since you are in very close range, it works well as both a strike and a shove to knock your opponent backwards. (fnt. 4)
Shuto uke chamber

Option 4

This defense use:
  • Back stance knifehand strike
  • Front stance high punch
  • Bringing the front leg back in
We're going to use the knifehand strike as the block. Although this might seem odd, it actually goes back to the karate roots: remember that one of the applications for the shuto uke chamber for is a roundhouse punch defense, using the straight arm to forcefully push down the opponent's punch, while the other hand comes up to defend the face. Basically, it's using the strength of a straightened arm to push the punch down and away. This is sometimes referred to as an "intercepting block". The only difference from the shuto uke chamber is that now we're going to step in with the same-side leg that we block with.

An intercepting block
From here, we're going to use an outside trip throw. Circle around your opponent's legs, and hook their head with the high punch. Following the footwork in the form, move your front leg backwards -- sweeping out their leg -- as you push their upper body downwards. This completes the outside trip throw. The name of this type of throw (hooking the head with your arm) is "tenchi nage" in jujitsu and aikido.
Intercept block followed by head hook (tenchi nage). Source: Aikidoflow
Conclusion

So there you have it: four ways to defend against the roundhouse punch

1) Use both arms to block. This is a good emergency technique when you don't know what else to do.
2) Parry and enter as your opponent opens up
3) Raise your elbow to block
4) Use a strike to intercept the punch

Notice that we end with a takedown whenever possible. This is because it gives us an opportunity to run away, and very rarely is there any follow-up after a takedown in the forms.

Footnotes
  1. The karate version of this move is usually described as a simultaneous high block and uppercut. While this is an appealing move, it doesn't fit the taekwondo version due to the trajectory and placement of the front fist.
  2. You might be wondering "what about the third punch?" Whenever forms use three moves in a row, it's actually two moves that constitute the application. The third one is put in for symmetry, since it's like you are performing two moves on both sides.
  3. Modern boxers use a short guard because the large gloves provide a large surface area to defend their head. Bare-knuckle martial arts almost universally use a long guard because your arms have more surface area than your fists. 
  4. I've read that forearm strikes were a thing in bare-knuckle boxing, but I'm having difficulty finding a primary source. Quote from this article: "Bare knuckle fighters hit with the outside forearm and scrape the entire ulna bone along the opponent's face. The strike is a combination between a punch and a shove. It's also a good way to avoid a broken hand. Solid contact will get the other fighter to bend over or move backward, which sets him up for a knuckle punch, a second heel hand, a hook punch or an uppercut." Forearm strikes are definitely used as shoves in Chinese martial arts.

Monday, December 26, 2016

Throwing in Choong-Moo, Part 2


I apologize in advance for all the gifs your computer has to load. It’s difficult to talk about these throws with just static images. In this post I'll cover three more throws found in Choong-Moo, once again using the more commonly known Judo names.

Cross body o soto gari (large outer reap)
An o soto gari
O soto gari refers to any throw where you reap the opponent's cross-side leg out from the outside as you pull them off-balance. The cross-body version pulls your opponent at a 90-degree angle before reaping. The reason being is that -- being a lateral throw -- it is much more difficult to counter, as the opponent cannot simply step backwards to avoid leaning over.


Application for flat spearfinger thrust
We'll start the defense with the flat spearfinger thrust in response to a grab. Although this move is usually portrayed as directly striking the eyes, I wouldn't recommend going for such a small target. Instead, a more practical application for the move is a palm strike to the chin that turns into a flat spearfinger thrust as you claw down into the eyes, a move you commonly see in self-defense circles.

The move has other uses. You can dig upwards into the opponents's throat, for example (this was Gichin Funakoshi's application). In the gif I provided, the defender uses flat spearfinger thrust as an intercepting block, before following up with an elbow strike with his back arm. If you shoot the spearfinger thrust on the other side of the opponent's head, you can transition into a headlock. The back hand for the guarding block can also be an inward strike to the neck. The exact move you do isn't important; so long as you neutralize your opponent in some way.

That said, the fact that the guarding block is open-handed is rather strange. One possibility I've read (from a karate guy) is that the movement can be used as a "lever" against a double lapel grab. The spearfinger strike will push the opponent backwards, straightening their arms. Use both your arms to push the opponent over 90-degrees (knifehand guarding block).


You may then place your right leg behind theirs while grabbing them (bending ready stance A to the back), and reap it out (side kick to the back) to perform the throw.


Application for moves 4-7 of Choong-Moo. Note that the perspective for the first three example images is mirrored.
Of the five side kicks in the form, this is the only one preceded by the bending ready stance.
Kani basami (flying scissor takedown)


Kani Basami
If you've ever wondered why there's a step-flying-side kick out of nowhere in Choong-Moo, it's likely a stand-in for kani basami, sometimes called a "flying scissors throw" or "crab claw throw". The initial step you take is for positioning: getting your front foot in front of your opponent. Jump up and scissor your opponent between your two legs, then twist your hips to take them to the ground.

This throw is infamous for breaking the leg of the judoka Yasuhiro Yamashita in the 1980 Summer Olympics. As a result, it is banned in Judo and most BJJ tournaments. But is it good for self-defense? Maybe. I'd avoid performing this on a hard floor, but it can a quick and effective takedown if you are grabbed from the side. It's also very surprising and difficult to counter.
Werdum's flying side kick

I've noticed that some taekwondo-ists perform a step-pump-side kick for this move. This appears to be incorrect: there is no frontal pump in the instructions for Choong-Moo (or anywhere in the Encyclopedia for that matter) (fnt 1). Instead, the flying side kick is like a skipping side kick with a jump; your back leg never travels in front of your front leg. So if you're wondering how a frontal pump relates to kani basami, the answer is that it doesn't.

This isn't to say that the flying side kick isn't a useful technique in its own right. We saw it used recently in the UFC (Werdum v Brown). Flying kicks also make very good conditioning tools: develop leg strength, balance, and coordination, all of which are transferable to other techniques.

Kata Guruma (Shoulder wheel throw) aka Fireman's Carry


Kata guruma
Kata guruma is the usual application I see for the U-shaped block followed by the jump and 360-degree spin. The use of the U-shaped block is obvious: it’s the pickup part of the throw. The bottom arm traps the opponent's leg and the top arm traps the opponent's arm. The jump represents lifting with your legs; notice how the thrower squats low before lifting.

But why the spin?



I’m pretty sure wrestlers just do it for show. Even the version of kata guruma in the Encyclopedia doesn’t include a spin. What gives? (fnt. 2)

Stuart Anslow’s explanation is that only the first 180-degrees of the turn is part of the throw, followed by a backwards dump, and then the remaining 180-degrees is just turning to face your now downed opponent. Here’s my interpretation of how the move works as kata guruma.


You begin by using U-shaped block from a knees-bent position against a standing opponent. Instead of relying on your arm strength alone to lift them up, you turn and sort of bump your shoulders into them as you rise upwards (the "jump"), placing them on your back. You occasionally see Judoka do this (see right gif). The judoka turns to initially help lift their opponent, and then keeps turning to control them as they try to escape.

The placement of the throw in the form would also make sense, since the next throw in the form (kuchiki taoshi) can be used in case your kata guruma fails. Both throws involve gripping the opponent's inner leg.


Conclusion

Between these two posts, I believe I've provided applications for roughly half of Choong-Moo. Although next post I'm going to return to a different subject, there are many other throws and takedowns to be discovered within the forms. Not all of them have Judo equivalents: many of them involve head cranking, for instance, or sweeping the legs with a kick, both of which are illegal in Judo.

I thought I'd leave you with this video from Karate Culture. It's about karate (obviously), but it has a similar theme to these posts: showing how you can learn form applications by finding the motions in other arts.



Want even more throws? Check out throwing in Po-Eun.

Footnotes

1) The frontal pump appears to be a recent taekwondo innovation, likely added to help students with insufficient leg strength do jumping kicks. In the Encyclopedia, jumping kicks are either done straight upwards or after a running start.
2) Apparently this jumping spin also appears in a karate kata. Iain Abernethy's explanation is that it's a stomp to your opponent's head after throwing them. Personally I don't buy this: there is no reason to jump or spin 360-degrees to perform a stomp. If anything, that's going to make your stomp very difficult to aim.

Sources
https://gfycat.com/SpicyIcyKob
https://www.youtube.com/watch?v=dEpHGqn4Wjg
Stuart Anslow. Ch'ang Hon Taekwon-do Hae Sul - Real Applications to the ITF Patterns: Vol 2

Tuesday, December 20, 2016

Throwing in Choong-Moo, Part 1

Instructions for an inner-thigh
throw (uchi mata)
One funny thing about most traditional martial arts is that most of them started out as comprehensive fighting systems, but eventually became more and more specialized. Grappling arts like Judo and Aikido used to contain strikes (atemi), for example. And conversely, karate and taekwondo used to contain locks and throwing. “Used to” may not be the best choice of words, since they are still officially part of the art.  There are sections on throwing in both the Encyclopedia of Taekwon-Do (ITF) and Kukkiwon Textbook (WTF). However, as sport taekwondo became popular -- in which grappling is illegal and the use of strong kicks is paramount -- clubs gradually shifted more towards kicking and actually stopped teaching most of the art.

But the throws aren’t just in the Encyclopedia, they are also contained in the forms. One form in particular that contains many throws is Choong-Moo. In this two-part post, I will be detailing six of the throws you can find in Choong-Moo, as well as a contingency single leg takedown at the end of the form. I'll refer to the throws by their more commonly known Judo names. The throws are:

Kuchiki Taoshi (One hand drop)
Koshi Guruma (Hip wheel throw)
Morote Gari (Both arms reap)

Kuchiki Taoshi (One hand drop)


Application for moves 20-21
This throw is pretty simple to perform, so much so that variants of it appear in other forms. Reach and grab opponent’s leg from the inside (low upset spearfinger), and then pull it upwards while pushing their body downwards with your front forearm (backfist-low block combination).

There are two variants to this throw worth mentioning. Instead of picking the inside of the opponent's leg, you can pick outside of it. However, in this case you want to turn 90-degrees as you pull back to increase the chance of takedown, as is done in the opening moves of Toi-Gye (moves 2-3/5-6).

If you pick the ankle instead of the knee, then this throw is called kibisu gaeshi ("heel reversal"). This is the version shown in the Encyclopedia, performed from a kneeling position. Although considered a different throw in Judo, the principle of the throw is still the same.
Ankle pick from the Encyclopedia
Koshi Guruma (Hip Wheel Throw)

The hip wheel throw is performed by wrapping one of your arms around your opponent’s head, thrusting your back hip deep into your opponent’s body, and then wheeling them over you as you pull their arm and neck. In other arts it's called an "arm and neck throw" or a "cross-buttocks throw."
Hip wheel throw
The throw itself is moves 22-23, but can be set up with move 21. If an opponent grabs you, you can use move 21 to pull your opponent towards you (backfist to back) while striking their core region with a hammerfist (front hand low block). The intent of this combination is to force your opponent to bend over, lowering their head.

To move into move 22, raise your left arm over your opponent’s arm and push downwards (supporting hand), while you shoot the spearfinger thrust to the side of their head with your right arm. You may now grab their arm with your left hand and wrap around their head with your right arm.

The reason I think this represents hip wheel is because of the very deep pivot you do for move 23. You do a three-quarter turn into front stance. The reason this throw is called the Hip Wheel is because you thrust your hip in deep and pivot as far as possible. Also, you end up in double front block, which pulls your opponent laterally over your hip rather than straight downwards. The front arm of double front block pulls your opponent’s arm, whereas the back arm is still wrapped around and pulls your opponent’s head.

Application for moves 21-23
Morote Gari (Both arms reap) aka Double Leg Takedown, and contingency throw


The twin palm upward block is one of those motions that draws a lot of blanks from Taekwondoin. I've seen suggestions that it represents some secret Hapkido arm lock. However there is an application for it -- and the preceding x-knifehand checking block -- that is actually pretty simple. But to lengthen my word count, let’s talk about the difference between a Judo double leg takedown and a wrestling double leg takedown.


Wrestler's entry (left) vs Judo entry (right)
Wrestlers usually enter with their head on the same side of their opponent's torso as their lead leg, whereas for morote gari, you place your head on the opposite side that you step forward with.


What this affects is the approach and the finish. In wrestling you usually do the double leg takedown with a dive onto one knee, under your opponent’s arms. This is a high-risk, high-reward move. It’s high reward because if you succeed in scooping your opponent’s legs, you will almost invariably bring them to the ground. Diving in with your head to the same side as your lead leg allows you to “cut the corner”: raise your opponent’s leg while driving sideways with your head, throwing your opponent downwards while also protecting you from a guillotine choke. It’s high-risk because there’s a simple counter to it: the sprawl. And if any opponent sprawls on top of you, then can pin you to the ground.

For the Judo double leg you approach more upright, driving forward with your shoulder. You can either scoop directly back and up (like in the form and the gif above), or out to the side in a shoveling motion. Olympian judoka Matt D'Aquino demonstrates these two options in the video below.

What about the x-knifehand checking block? Well, using the same application from the gif above, it’s just a setup to raise or push apart your opponent's arms before you come under to do the leg scoop. Ideally you will break your opponent's grip, though I think this is unlikely for a strong opponent.


Snapping an opponent's head down to set up a double leg,
demonstrated by Olympian Jordan Burroughs.
As a variant, the x-knifehand checking block could represent putting your opponent into a clinch. This, in fact, is how some wrestlers set up the double leg takedown: if you snap down your opponent's head, they will naturally want to rise back upwards; you take advantage of this by diving in and scooping up the back of their knees.


The weakness of morote gari is that it has a pretty simple counter: stepping backwards with the leg opposite-side to your head. Luckily, the form takes this into account and follows up with a single leg takedown. Specifically, you turn 180-degrees (half steps) while raising the leg you do have a hold of (high block) and finish the throw by pushing your opponent outward (back hand punch). This completes the form. This is actually quite similar to (though not completely the same as) a contingency throw that Iain Abernethy performs in the pics below. Both involve lifting the leg, however Abernethy does not do a 180-degree turn. Instead he trips his opponent and then keeps driving forward.


Abernethy's contingency throw for a failed morote gari. Whole video here.
With that, we can define the last four moves of Choong-Moo to be as follows:

1) Opponent grabs you with both arms. Raise up your arms through their grip (x-knifehand checking block)
2) Spread and push up opponent's arms (set up for twin upward palm block)
3) Step in and grasp the back of opponent's knees, and pull upwards to throw (twin upward palm block)
3b) Opponent defends by stepping one leg back
4) Raise up the leg you do have while half-stepping to turn 180-degrees (high block)
5) Finish throwing opponent by pushing out their body (back hand punch)

Application for moves 27-30 of Choong-Moo
Conclusion

Although it's commonly believed that Taekwondo contains no throws or locks, there is evidence of both in the Encyclopedia and in the forms. They are not primary to the art, and are really only used if an opponent grapples you. However, I don't believe you can have comprehensive self-defense knowledge without knowing something about throwing, and clearly those who put the forms together thought the same.

Want more throws from Choong-Moo? Check out part 2.
Sources

https://www.youtube.com/watch?v=Rlf4JHgLt_Y
https://www.youtube.com/watch?v=DFXyctwr6Kw
https://www.youtube.com/watch?v=gyXhysmMNhE
https://youtu.be/cd1FJKT3ewI
https://www.youtube.com/watch?v=HjECUUkOQ3Q
https://www.youtube.com/watch?v=xi8MmLyD4ps
https://www.youtube.com/watch?v=j_BkUZ3wOQA
https://www.youtube.com/watch?v=Gp6NAnFPF7s
https://www.youtube.com/watch?v=y6Kpbs1OLwA
"Traditional Taekwondo Forms, vol. 1" (DVD) by Grandmaster Tae Sun Kang


Thursday, December 15, 2016

Chon-Ji 2: The Front Stance Middle Punch

If you have not read part 1 yet, you may find it here.

A lot of arguments about the utility of forms can be traced around the front stance middle punch -- sometimes referred to as the “lunge punch” in karate. Because, let's be honest, who punches like this?


Taekwondo of course is filled with “official” answers as to why we perform the front stance obverse punch the way we do:

Why do we circle our foot in before moving forward? Because it allows you to maintain balance (equilibrium) by bringing the foot in.
Why do we reach out with the back hand before closing it and pulling it in towards our hip? You reach out to track your target. You pull back in for reaction force, strengthening the punch
Why do we punch from the hip? For power, or to practice full range of motion.
Why do we keep our hips and shoulders square? To avoid over-committing to the punch.
Why do we sink into a front stance? For stability or to increase the power of the punch.

While there is some truth in these explanations, they still seem unsatisfying, because the downsides to this type of punch simply outweigh the benefits. Isn't just stepping forward faster? Is the extra power from “reaction force” worth dropping your guard? Doesn’t the front stance decrease your mobility and leave you vulnerable? And the bit about avoiding over-commitment seems silly given that the move includes quite a bit of over-commitment already.
Boxer's jab

The lunge punch is often compared to a jab, but the truth is that the two moves are nothing alike. Boxers aren't afraid to put their hips and shoulders into their jab, for example. And despite the lunge punch's reputation as a "power move", it really isn't all that powerful. I'd trust a good reverse punch over it any day. That's probably why some suggest that a lunge punch is really supposed to be a reverse punch with a following step.

It is my view that -- similar to basic blocks -- we’re not training a punch so much as we’re training a motion, which can be applied in various ways. Honestly, the technique should probably be called “forward forefist pressing motion”, but that’s a bit of mouthful compared to “punch”. While "reverse punch with a following step" is a possible application for the motion, there are several others.

With this in mind, we can stop trying to pretend that the move works well as a punch (it doesn't) and try to see what can extracted from the elements of the move.

Why do we circle our foot in before moving forward? Circling the foot can represent circling around one of our opponent’s legs, usually for an outside trip or inside trip throw.
Why do we reach out with the back hand before closing it and pulling it in towards our hip? The setup hand has multiple uses: it could represent a parry before striking, pushing down an opponent’s arm, or grabbing the opponent to pull them.
Why do we punch from the hip?  The movement isn't just a punch, it could represent any sort of "push" motion. Many throws are executed body-to-body, and thus having the strength to push from the hip is important.
Why do we keep our hips and shoulders square? To keep our body upright in a grappling situation; any loss of balance makes us vulnerable to a throw.
Why do we sink into a front stance? The front knee can be used to "wedge" into the back of an opponent, unbalancing them.


And old-school karate takedown.
Like the basic blocks, this motion is a template for multiple applications. As such, you will not use all elements of the move all the time.

But the point of this post is not to enumerate all the possible uses of the front stance middle punch. Instead, I'm going to look at its use in Chon-Ji, and try to come up with something that I believe is more reasonable for self-defense than what is usually provided.

Chon-Ji: Deflecting inward

Let’s use the two applications I discussed for low block and inner-forearm block in my previous post, and see how the front stance middle punch would apply as a follow-up in either case. After striking the groin with the low block, the next move may be used as a throw.
  1. Opponent throws a straight punch. Step outside and parry inward, before passing and trapping with back hand (low block chamber)
  2. Strike opponent's groin with hammerfist (low block)
  3. Circle your back leg forward. Due to your positioning, you are actually circling behind your opponent's leg (movement into front hand punch)
  4. Use the setup hand to grab the back of your opponent's shirt (setup for front hand punch)
  5. Simultaneously pull the back of their shirt into your hip while pushing them over your leg with your front arm (front hand punch)
  6. If this fails to take them to the ground, sweep out their leg by moving your front foot back in (movement into next low block)
I call this an "outside trip throw". It's a common throw in karate and taekwondo, and has several variants. Instead of grabbing the back of their shirt, for example, you might use the setup hand to press on the small of their back, as in the gif below.

Outside trip throw, pressing the small of the back.
Personally I prefer the pull-push version. It feels more like the way we do the form. The closest equivalent Judo throw is o soto gake (large outer hook).


Following the inner-forearm block

The other combination in Chon-Ji -- that often receives less analysis -- is an inner-forearm block followed by a lunge punch. Near the end of the form (moves 15-17), we performed an inner-forearm block followed by two lunge punches. What’s going on?

If we use the parry-pass application for inner-forearm block, then you can’t use the o soto gake throw from this position, because you stepped forward with the inner leg. Instead, we just follow up the block by using front stance middle punch as (wait for it) a punch to the floating rib. The pulling hand in this case traps your opponent's shoulder so they can't retreat from you as you punch.

Trapping and using a punch after the inner-forearm block
Why the step forward? In the video where I take the above image from, it's suggested that the opponent retreats for a better position after being grabbed, so the step is following them. In our case we have another reason: positioning. We are now in a position to use the o soto gake throw, represented by the second front stance middle punch. After this we begin moving backwards; which, as I mentioned above, could represent sweeping out the opponent's leg.

Another example. Parry-pass-strike, followed by outside trip throw.
So to recap, these two applications to Chon-Ji are:
  1.  Parry pass a straight punch stepping outwards (low block chamber)
  2. Strike the groin (low block)
  3. Circle behind their leg and throw (front hand punch)
And
  1. Parry pass a straight punch stepping inward (inner-forearm block)
  2. Step in and punch (first front hand punch)
  3. Circle behind their leg and throw (second front hand punch)
What about the end of the form, where we perform two front hand punches moving backwards? Although I'm not certain, I think these can represent a counter to an outside trip throw. Stepping back into something resembling front stance is, in fact, a common counter to the Judo throw o soto gari. You do this to deny your opponent the off-balancing they need to throw you. You then perform a counter-thrown, which amounts to moving backwards with your other leg.

O soto gari counter. Step back into front stance with free leg to maintain balance, then counter-throw with caught leg.
As I mentioned in my post on Joong-Gun, sometimes a form will provide a counter to a technique earlier in the form.

Conclusion

If you were to construct a martial arts system, what self-defense techniques would you want a white belt to know? Would you want the first thing they practice to be a defense against a front kick, or against a punch? Would you teach them to counter with an awkward, highly rigid lunge punch; or a hit to the groin? Would you forgo a finishing move, or teach them a simple but high-percentage throw? Would you construct a form where only a small portion of the movements have a purpose, or a form where nearly every movement mattered?

I'm not saying that mine are the "right" applications, but I believe it's worth thinking up better applications than the standard ones usually given.

Sources

http://bleacherreport.com/articles/1960174-lyoto-machida-old-school-karate
https://www.youtube.com/watch?v=GjVNMhcBdm4&t=26s
https://www.youtube.com/watch?v=FtCNLzsfrkg
https://www.youtube.com/watch?v=zFepc4Z7f88
https://www.youtube.com/watch?v=SMvo4tWnYE0
Dan Djurdjevic's two excellent posts on the lunge punch
http://dandjurdjevic.blogspot.com/2013/02/lunge-punches-why-bother.html 
http://dandjurdjevic.blogspot.com/2013/02/step-through-lunge-punches-as-stem-cell.html