Thursday, October 19, 2017

9: Po-Eun leg lift

Source (right image): MEMAG
The final two moves of Po-Eun are
  • Cross step into X-stance low front block, with the opposite palm hitting the the side of the fist
  • Step out in the same direction into riding stance low ridgehand guarding block
Unlike the knifehand low front block in Kwang-Gae, there are no instructions for the movement to be circular. Personally I prefer grappling interpretations for Po-Eun; the preceding set works well as a headlock defense, for example. However, the low front block is usually explained as blocking a front kick, so I think it's worth first exploring that application.

Front kick defense

First question: can the movement be practically applied against a front kick? Yes, actually, but not in the way you might think.

You never want to block a front kick straight on. Rather, you want to get off the line of fire and deflect the kick. One simple way to do this is by twisting your body. Take a look at the gif from one of Dan Djurdjevic's older videos.
Source: Dan Djurdjevic
Notice how after twisting, he takes a cross step in towards his opponent. He uses his front arm not as a hard block but rather as a deflection. So the X-stance low front block does work against a front kick, but the trick is that you should be facing sideways from your opponent. We can use the opposite hand (the palm hitting the side of the fist) to catch the leg after deflecting.

What's neat about this defense is that it works no matter what leg the opponent kicks with, and we can still utilize the ending move of Po-Eun as a takedown. If you catch the leg from outside, then you just use your forearm to press down your opponent's torso while lifting their leg.

But what if you catch the leg from inside? This is where the grappling interpretation comes in.

Leg lift with inside trip

Suppose we are not facing a front kick but are rather in a grappling situation. The low front block can be used as a two-handed leg pick, using the cross step to get close. You then step through the opponent's legs into the riding stance, setting up an inside trip, and lift their leg. The chamber for the guarding block -- raising both arms back -- comprises the actual throw, but as the opponent falls your arms naturally go into the low ridgehand guarding block position.
Source: MEMAG
If you catch an opponent's front kick from the inside, you can use this throw as well.

It's worth noting that the source video shows two counters to this throw, one of which is just a strike to the thrower's head. Using both hands to grab a leg leaves your head exposed, so think carefully about when it's proper to apply this technique. You might apply the previous two moves in the form as strikes: an elbow strike to the throat followed by a low hammerfist to the groin. This will distract your opponent and allow you to go for the leg lift. As before, you should be facing your opponent more-or-less sideways.
Striking applications for the preceding two moves (15-16/33-34).
Sources: DTDTRyan Parker

Friday, October 13, 2017

8: Joong-Gun and Ko-Dang revisited

In this blog I've provided a comprehensive analysis of three ITF forms: Joong-Gun, Ko-Dang, and Kwang-Gae. Since then, I've gone back through the sets and made little changes based on a better general understanding of applications. In this post I want to revisit two sets: the roundhouse kick defense in Joong-Gun (moves 20-22/23-25) and the guarding block followed by double block in Ko-Dang (moves 3-4/7-8).

Joong-Gun roundhouse kick defense

Rather than use the double forearm block itself as the kick defense, we use the set-up as the defense, stepping forward and away from the kick while we prepare to use our back arm to either under or overhook the opponent's leg[1]. We use the front arm as a strike, such as a backfist or uppercut to the face, or simply just a ram with our forearm, knocking the opponent off-balance.

The footwork for the set is to semi-circle forward into front stance for the double forearm block, pull the front foot back in, then step forward into back stance as we punch with our front hand. Use this footwork to circle around and sweep the opponent's standing leg. If they don't fall, we then use the "punch" as a push, knocking them to the ground.
Sources: Southern Minnesota Martial ArtsCurransKarate, Arirang Culture
So if the double forearm block (with chamber) and the punch comprise the defense, then what is the point of the third move in the set, the side kick? It could be an alternative takedown: kicking in the opponent's standing knee in case we catch the roundhouse too far to sweep. Another possibility is that it's to help escape an opponent who attempts to pull you to the ground with them. Side kick the groin or torso of the downed opponent until they let go of you.

Ko-Dang tackle guard and arm break

Front leg grab after a tackle block.
Source: Code Red Defense
Stepping backwards 45-degrees into guarding block is a good, basic tackle defense. But I was mystified by the following move, where we transition into a simultaneous front hand inner-forearm block, back hand low block while maintaining our stance. In retrospect, the application is pretty simple. Your opponent may still be able to grab your front leg or waist as you guard, but because you are pushing their head back their arms will have to be extended. Thus, you simply use the inner-forearm block to hyper-extend one of their arms, as shown by kukki-taekwondo master Dong-Hee Lee[2] below.
Source: Dong-Hee Lee
The simultaneous back hand low block may be used to break the opponent's other grip, traveling in between their two arms.

Another option is to simply break the arm you already have a hold of after the guard (the fact that you use closed fists in the form indicates that you are grabbing). Use the low block to pronate the opponent's arm, so that their elbow faces outward, and the inner-forearm block to strike the outside of the elbow. The positioning is a little more awkward, but a quick hit could end the fight.
Sources: TKDdragon, MEMAG

As I've stated before, there are other ways to interpret these forms, but I think it's neat that you can find a thematic framework to them. I'm considering writing a comprehensive analysis of the Original Koryo; it's not an ITF form but I was impressed with it enough to learn the movements, and it's easy proof that the Kukkiwon forms (at least the older ones) have applications as well.

[1] The subsequent counter given in the form assumes an overhook. I've noticed that a lot of traditional martial artists teach to underhook a roundhouse kick, but Muay Thai fighters overhook. This may be because an underhooked roundhouse is easier to escape via spinning out, i.e. continuing to turn in the direction of the kick.

[2] I have to thank White Dragon Dojo for the introduction to Dong-Hee Lee, who has various youtube videos showing applications (mostly striking) to kukki-taekwondo poomsae.

Thursday, October 5, 2017

7: Chon-Ji sparring combinations

One unfortunate thing taekwondoin find about their forms is that most of the sets can't be used in sparring. ITF taekwondo sparring is kickboxing-lite, and you are not allowed to grab your opponent, but most forms are designed for grappling situations.

However, you can sometimes rework sets into combinations usable in sparring. Two examples of this are the sets from our white belt form, Chon-Ji.

  • Front stance low block
  • Front stance middle punch
  • Back stance inner-forearm block
  • Front stance middle punch
Instead of treating these movements as one block followed by one strike, you can rework them into three strikes each.
Source: Advanced Karate Techniques
In the above image, the karateka uses the low block chamber (the karate version) as a simultaneous side parry and punch. He then follows with the hammerfist strike, and then steps forward with a jab.

Below, Ryan Parker applies the inner-forearm block in a similar fashion. He uses the chamber as a down parry and punch, and then follows with the block-proper as a strike to the side of the neck. Personally I find that in sparring the motion works better as a rolling backfist to the face. Just like with the low block, after the two strikes you follow with a step forward and jab.
(Left) Inner-forearm block as two strikes. Source: Ryan Parker.
 (Right) A rolling backfist. Source: Tao of Peace Martial Arts
So to recap, the two striking sets are:
  1. Simultaneous side parry with front hand and punch with back hand
  2. Low hammerfist
  3. Step forward and jab
  1. Simultaneous down parry with front hand and punch with back hand
  2. Rolling backfist to face
  3. Step forward and jab
You can work this into a simple shadow boxing drill. Practice the first combination. Then, since you stepped forward for the jab, repeat on the other side. (This way you're also practicing a jab-cross). Now the do the second combination, and then repeat it on the other side. Practice switching between these two combinations so that you can pull them off quickly with muscle memory alone.

Defending a jab-cross

Another reason we chamber basic blocks to block two punches, not one. If your opponent throws a high jab-cross, for example, we can use the inner-forearm block against both punches. So the set would be as follows:
  1. Down parry jab while counter-punching (chamber)
  2. Deflect cross outward (inner-forearm block)
  3. Step forward with your own jab-cross
Jab-crosses are commonly thrown as different levels, so if your opponent throws a high jab-low cross, then you may perform the low block as the second defense instead.

Tuesday, October 3, 2017

6: Choong-Jang arm drag to rear naked choke

Here's an application straight out of a jujitsu class. It uses the set from Choong-Jang:
  • Back stance low ridgehand guarding block (move 37/39)
  • Stance shift into front stance nine-shape block (move 38/40)
  • Chamber for move 41, i.e. crossing both arms across chest while moving backwards
The use of the first two movements are shown in the gif below.
Source: Relson Gracie Jiu-Jitsu Academy
  • Use the guarding block chamber as a "wax off" motion against a push or attempted grab.
  • Circle downwards, gripping the opponents wrist and triceps with the back and front palm of the guarding block respectively. (For the ridgehand guarding block, both palms face upwards)
  • Pull to the side while stepping forward behind the opponent, getting to their back. 
  • Use the upper arm of the nine-shape block to get a choke, while you use the lower arm to press on the opponent's lower back, breaking their structure. 
  • You can then use both arms to do the choke as you drag your opponent backwards.
Using the lower arm of the nine-block to break the opponent's structure is not a trivial step. The rear naked choke is difficult to escape once balance is lost. Other tutorials recommend you use your knee to break the opponent's balance instead, such as this one by Stephan Kestling.

I admit that I am adding extra footwork to the form (stepping forward while you pull) and changing the nature of the nine-block somewhat. But I believe this is a good self-defense technique for any taekwondoin to know: arm drags and rear naked chokes are both grappling staples. The fact that the next movement in the form is to literally move backwards while crossing your arms leads me to think I'm on the right track; this is how Stephan Kestling mimes the movement.
In Stephan Kestling's version of the rear naked choke, the knee is used to break the opponent's structure.
Source: Self Defense Tutorials
I also believe this to have a higher chance of working than the usual "joint break" application given for the nine-block, where the lower arm pulls down the opponent's wrist while the upper arm rises under their elbow. This may seem like a good application for this set on first glance, but it's unlikely to work against a resisting opponent because it relies on weak shoulder muscles. A better way to break with the nine-block is to overhook the opponent's arm and get a figure-four lock, shown in the bottom half of the below image. This is more stable and lets you use stronger muscles to break. I believe this is the use of the nine-block in Gae-Baek, but it does not fit the movements in Choong-Jang.
Top: "Joint break" application for the nine-block from the Encyclopedia of Taekwon-Do. I have doubts about this application. Bottom: A different way to break with the nine-block.
  Sources: Total Self Defense, Radek Scuri

Monday, October 2, 2017

5: Choong-Jang head crank with thigh kick throw

Source: David Veiras
Traditional forms are often confusing at first glance. But when I first saw Choong-Jang I thought, "This form I get. This looks like a self-defense form." The form has eye pokes, throat strikes, low kicks, strikes with the elbow, strikes with the palm heel, and downward throwing motions. Choong-Jang borrows heavily from the retired form Woo-Nam[1]. Studying differences in the sets might reveal things about the form's design.

In this post I'll provide an application for the set
  • Back stance knifehand guarding block
  • Step and slide forward into back stance side elbow strike
  • Shift into back stance knifehand guarding block
  • Front leg side kick
  • Land turning 180-degrees into cat stance twin palm pressing block
Use the first move as a block (using blocks as blocks; how novel), deflecting an opponent's attack inward. Grab their arm and pull it towards your hip (reaction hand) while striking their ribs with your elbow. The slide is used to increase the strength of the strike and bring you closer to your target. From here we'll add a small hidden move: a shoulder bump, which will force our opponent to lower their head.

Source: One Minute Bunkai
Inner-thigh lift throw from the
Encyclopedia of Taekwon-do
So far so good? Next, use the second knifehand guarding block as a head crank. Grab the opponent's head with the chamber (right hand under, left hand on top), and use the "block" to crank the opponent's head counter-clockwise, from your perspective. (Aside: if you haven't been following, this is a common alternate application for the knifehand guarding block. If you bring your palms in parallel, it's like you are holding a head in between them). To complete the throw, kick out their left thigh with the front leg side kick. Turn 180-degrees and continue to crank their head, eventually pushing it to the floor (twin palm pressing block).

The throw is mechanically similar to Judo's uchi mata (inner-thigh lift throw), which appears in the throwing section of the Encyclopedia of Taekwon-Do (right image). In an uchi mata, the kick is used between the opponent's legs in order to lift up their inner thigh. Also, in modern Judo a skipping side kick, rather than a simply front leg side kick, is used to get more leverage. In Choong-Jang I think the intent is more to kick back the opponent's leg, but if you miss the front thigh then you can turn the technique into an inner-thigh lift throw instead.

Please note that this application can potentially hurt someone's neck. Grabbing your partner's clothes while practicing the throw is safer.

Bonus: Woo-Nam version

This set has changed from its original version in Woo-Nam. In this version, the movements after the side elbow strike[2] are:
  • Bring both fists to the right hip ("cup and saucer" or "small hinge" block), while raising the left leg
  • Left leg side kick to the side
  • Land forward into back stance twin palm pressing block
In this case the throw is just an o soto gari with a head push.[3]
Left: The set from Woo-Nam, performed by C.K. Choi. Source: Byresha Boraiah
Right: An o soto gari throw
O soto gari throws are common in the forms. Perhaps that's why when Choong-Jang was made the set was reworked into a different kind of throw.

[1] The reason Choong-Jang is part asymmetric and part symmetric is that the asymmetric sections are based on Woo-Nam, whereas the symmetric sections are new material added by Kim Bok Man and Woo Jae Lim, who made symmetric forms. Woo-Nam is often referred to as "U-Nam", but according to C.K. Choi this is not the proper pronunciation.

[2] In some performances of Woo-Nam, a front stance upward elbow strike (with the front arm) is used instead. It's hard to say which is the original version, but the intended application seems to be a strike.

[3] The opening set of the original Koryo (a Kukki-taekwondo form) has the same application, except a low X-fist block is used to push down the head.

Monday, September 25, 2017

Thoughts on the Kukkiwon forms

Use of the reaction hand as an a pull from
a 1968 Taekwondo textbook. Source:
  Traditional Taekwondo Ramblings
This blog is mainly concerned with the ITF/Ch'ang Hon taekwondo forms. But what about the other set of taekwondo forms: those of WT/Kukki-taekwondo? In this style forms are known as "poomsae". The poomsae were invented a little later than the ITF forms, for an organization that wanted to make taekwondo a sport as well as a martial art. Hence, there is a lot of skepticism surrounding poomsae. How do taekwondoin know they aren't just random moves strung together? If they have applications, how did they become lost?

I haven't studied the Kukkiwon poomsae in any great detail (Organ Nilsen's blog Traditional Taekwondo Ramblings is a good source for that), but just from eyeballing many of the poomsae: they look like they have applications. That doesn't mean I know what the applications are, but the organization of the movements does not seem random and the movements are not just block-punch-kick.

There are three groups of traditional Kukki-taekwondo poomsae: the eight Palgwae forms, the eight Taeguek forms, and the nine (or ten) Black Belt/Yudanja forms. In this post I've briefly go over each group, and then touch on the new competition poomsae the Kukkiwon is developing.

The Palgwae Forms

The Palgwae forms were eventually replaced in favor of the Taeguek, but some WT schools still practice them. They are similar to karate kata in style, with deep stances and rigid movements. Like the lower ITF forms, they appear to be a mix of original sets and sets from the Heian/Pinan kata. There are eight Palgwae poomsae in total.

One thing I noticed about them is the frequent use of the front block (ap makki); that is, what Kukki-taekwondoin would call a middle block (momtong makki) or inward block. This movement is rare in karate kata and ITF forms, although both styles teach the movement in basics. If you look at Palgwae 1 for instance, it starts out with a low block just like Heian Shodan and Chon-Ji, but then moves into a front block instead of a lunge punch.

In fact, there are few "strikes" in Palgwae 1. I put that in quotes, because obviously "blocks" (makki) can be used as strikes. The front block makes a good hammerfist to the head (in fact, the inward knifeward strike, which is the same motion but with an open hand, is also in the form). It could also represent a grab or, if the opponent is lowered, striking with the elbow.
Striking application for the front block, using the pulling hand to control the opponent.
Source: Richard Conceicao
The forms that looks the most taekwondo-ey are Palgwae 6 and 7 due to the kicks, but they never get more complex than simple front and side kicks. All-in-all, I find these reminiscent of the lower ITF forms. The similarity to karate kata probably makes applications easier to find, but I'm not aware of any systematic study of Palgwae applications.

The Taegeuk Forms

In 1971 the Palgwae were replaced with the eight Taegeuk forms. These forms are simpler than even the Palgwae, although they do a good job of steadily increasingly in complexity. They are also similar to each other because they tend to use variants of the same sets. For example: the first two moves of Taegeuk 1 are walking stance low block followed by walking stance punch, whereas the first two moves of Taegeuk 2 are walking stance low block followed by front stance punch.

The most noticeable innovation with the Taegeuks is the frequent use of "walking stance", a high stance formed by simply taking a natural step forward. Walking stance is not used in any of the Palgwae forms; it was likely invented to distinguish the Taegeuks from karate kata, similar to the addition of the sine wave to ITF forms. Although this change is pointed to as evidence of Taekwondo's shift from a mixed grappling and striking art to a kickboxing art, deep stances are not completely absent from the Taegeuks, and we should remember that the merits of deep stances are debated even in traditional circles. I've read that Okinawan Karate used high stances, and even Gen. Choi wrote in his Encyclopedia that one's front stance must not be too deep. Chambers and the pulling hand are still present. The Taegeuks are also more strike-heavy than the Palgwae, including a wider array of kicks and elbow strikes.

Were the Taegeuks built with deeper applications in mind? Simon John O'Neil thinks so. His book The Taegeuk Cipher contains applications for all eight forms. Take this application for the end of Taeguek 5, for example, which is suspiciously similar to the end of our 5th form, Yul-Gok.
Application for end of Taegeuk 5 (left), very similar to the end of the 5th ITF form Yul-Gok (right).
Sources: Pal Kwon, Southern Minnesota Martial Arts
At the very least, the forms have some intelligent design to them. In Taegeuk 1 the first two low blocks are in walking stance, but the third low block -- performed with a 90-degree turn -- is in front stance, which singles the move out as a throw. Taegeuk 7 uses a ready position in the middle of the form. Some higher ITF forms do this as well, since ready positions have their own applications.

All that said, the Taegeuks are a frequency mocked set of forms for being too simple or being made by committee. You can read a defense of the poomsae here if you're interested.

The Black Belt/Yudanja Forms

Unlike the Palgwae and Taegeuk forms, the nine Yudanji forms are not a consistent set which build on one another. Each one was supposedly made to represent a different Kwon school, and it shows.

The 1st Dan form Koryo relies heavily on striking: including low and high kicks, elbow strikes, and throat grabs. Its ready position is reminiscent of the Heaven Hand from Kwang-Gae, although the orientation of the palms suggests it can be used as a direct strike to the opponent's face. There is a strange portion in the middle of the form where a slow motion, circular low target hammerfist strike is used; explanations of this movement I've come across include a strike to a downed opponent, a bear hug defense, or just centering your chi.
A Danish team's interpretation of side elbow strike followed by low section hammerfist as a dual strike to the opponent's ribs and groin. But wouldn't a low block after the elbow strike be better for this?
Source: DTDT
In contrast to the fast and dynamic Koryo, the 2nd Dan form Keumgang contains a number of slow-motion movements, no kicks, and a lot of repetition. It's an interesting form and I've seen some creative interpretations for it. Take the spinning angle punch, for example. It may seem bizarre at first glance, but it makes a good spinning armbar takedown.
Source: Pal Kwon
The 3rd Dan form, Taebaek, is the most karate-inspired of the set, being clearly based on the Heian/Pinan kata. There are some curious alterations, however. For the opening set of Heian Nidan, the hammerfist is changed to a punch, which is the same alteration that ITF taekwondo uses in Won-Hyo and Hwa-Rang. In any case, because it's based on the Heians it's fairly easy to guess applications for. [1]

Beside the nine Yudanja forms, there is a retired form called the "original Koryo"[2], which despite the name bares little resemblance to the modern Koryo. In fact, this is the original 1st Dan form; it was replaced with the modern Koryo around the same time as the Taegeuks replaced the Palgwae. It is surprisingly short, only 20 moves, but seems to enjoy a good reputation among those who study applications. Richard Conceicao has two videos (one, two) on this form.

Application for a set from the original Koryo ending in a low X-fist block. Source: Richard Conceicao
Officially it was retired for being too simple, which I find unlikely since although it is short it certainly isn't a simple form. The real reason for its replacement, like the Taegeuks, may have been political.

The only textbook on applications for the Yudanja forms I know of is Taekwondo Poomsae: The Fighting Scrolls by Kingsley Umoh, but it is not comprehensive.

Competition Poomsae

In the past couple years, the Kukkiwon has experimented with new, challenging poomsae for taekwondo competitions. 13 such forms have been invented (ten back in 2016, then the three recent Bee-Gak poomsae). Their introduction has been controversial, as they are clearly developed to show off taekwondo's athletic kicking techniques. Below is a performance of Bee-Gak 2.

Proponents of the new forms point out that the traditional forms don't represent what the art has become and these forms give students a chance to practice advanced kicks. Opponents state that this is a consequence of the sportification of taekwondo and the forms were not created with any practical self-defense knowledge in mind.

The new poomsae appear to be a mixed bag of kicking and traditional hand techniques. But it's not clear that these techniques have any meaning beyond looking cool. Several of the hand techniques are done in slow motion: is that for application reasons or because they provides an aesthetic contrast to the fast flowing kicks?

I will say a few points about the new poomsae. The first is that having poomsae specifically for competitions isn't inherently a bad thing, provided you keep in mind that's what they are for. Kukki-taekwondo has 17 traditional forms; 26 if you include the Palgwae forms and the Original Koryo. That's already plenty of self-defense knowledge. Second, just because a form looks incoherent at first doesn't mean it is. Karate kata applications were lost for decades, despite the fact that they are practiced world-wide. Forms just aren't made to have obvious meaning. Juche is an example of a "flashy" ITF form, but Stuart Anslow managed to find some interesting applications for it (yes, even for the split kick). Third, for all the disparaging of block-punch-kick applications, those aren't bad things to learn. Defending against and delivering strikes are more likely to help you in a self-defense situation than a complex grappling technique. My issue is that traditional forms simply aren't good at teaching block-punch-kick. The lunge punch doesn't exist outside the dojang, and no one chambers before blocking or pulls their opposite hand down to their hip. A true block-punch-kick form would look more like shadow boxing, which the kicking sections of the new poomsae sort-of approach.

[1] I don't mean that the Heians are inherently easier to understand, but rather that there is already a lot of online information about applications for the Heians.

[2] Some schools teach both versions of Koryo, and refer to them as "Koryo 1" and "Koryo 2". "Old Koryo" is also a common name for the original Koryo.

Sunday, July 23, 2017

Hae Sul 4: Gae-Baek elbow lock takedown

10-10-2017: There is a second, more literal application of the set I have added below.

So much for the first double arc hand block in Gae-Baek. Now for the second.

There is a locd called hiji kime osae (elbow arm bearing pressure) in Aikido and waki gatame (armpit lock) in Judo, We can use Gae-Baek moves 25-28 to create this lock. The set is:
  • Front stance double arc hand block
  • Maintaining stance, back hand upset punch
  • Half step 180-degrees into horizontal elbow strike, left palm hitting right elbow
  • Leap forward into rear foot X-stance double forearm block
Sources: HowCast, coshigould
Besides the source video, another example is here. Details
  • Assume a same side wrist grab against your right arm. Rotate your right arm counter-clockwise, and use your left palm to grab the back of the opponent's hand. (Double arc hand block)
  • From here you can grab your opponent's knifehand and peel it off and down with the upset punch, pronating the opponent's arm in the process, which allows you to...
  • Turn 180-degrees and match your elbow with your opponent's, putting them into an armbar. The left palm in this case is bending your opponent's wrist in towards their body, putting them into a secondary wrist lock.
  • Use the leap as a quick-and-dirty takedown. Put forward pressure on your opponent as you lean your weight on them and bend their wrist and arm towards their body with the double forearm block.
Aikidoka perform this lock more continuously, so step 2 -- using an upset punch motion to pronate the opponent's arm -- is barely noticeable because it's done while the defender is turning. The takedown can be done either by dragging the opponent out or by putting forward pressure on them. If you don't wish to harm your opponent, then don't use the literal leap. Leaning onto your opponent should be enough, and might explain the use of rear foot X-stance: placing all your weight forward.

The preceding move in the form -- the twin vertical face punch -- may be used as an initial strike: a quick pop to the face if an opponent grabs your wrist.


You may have noticed that the aikidoka first raises his opponent's arms to head level, just like our double arc hand block. However, other martial artists have argued this is a bad idea, and that it's better to keep your opponent's wrist close to your body. Alain Burrese, a Hapkidoin, says you never need to raise your opponent's arm above your armpit. He also performs the takedown by leaning back on his opponent and sitting down.
Source: Your Warrior's Edge
Although it's not a leap, you can still see the use of the double forearm block, bending both the wrist and arm in towards the opponent's body.

A more literal application

Block and palm strike application for
the double arc hand block.
Source: Kata for Self Defense
The use of the upset punch as merely transitional may seem like a stretch to some. There is a more literal application to the set I recently came across.

The double arc hand block can be used as an actual block, or more accurately a simultaneous block and palm strike, similar to the karate version of the open-handed twin block. It is aimed off at a 45-degree angle because you are blocking a hook punch with your back arm, while palm striking with your front arm.

After this you want to grab your opponent's right shoulder with your right hand. Why? To avoid head collision as you pull them in with the reaction hand. Perform the upset punch with your left fist as you pull them in. Now you have gotten your opponent to lower their head. Perform an elbow strike to it while turning 180-degrees, taking them off balance. To complete the set, use the leap into rear foot X-stance as a throw. The double forearm block acts to push the opponent's already unbalanced body.

The major problem with this application, I think, is that by pulling the opponent in so close they are very likely to bear hug you and take you to the ground with them. You might avoid this by repeatedly elbow striking their head before you do the throw. This may get your opponent to let go of you and try to defend their head, at which point the throw is safer to perform.