Uchidachi assumes hassō, and shidachi wakigamae. Both sides advance three smaller-than-usual steps. Upon reaching ma-ai, uchidachi, sensing an opportunity, raises the sword into morote-hidari-jōdan; shidachi immediately reciprocates, and both sides step forwards on the right foot to make a vigorous cut to the opponent’s shōmen, leading to the swords cutting into a deadlock (kirimusubi) in ai-uchi.
Following the ai-uchi, both sides, displaying equal kigurai, scrape the blades’ shinogi together to assume ai-chūdan. Uchidachi, sensing another opportunity, angles the edge to shidachi’s left, and, stepping in leading with the right foot and following with the left, thrusts with both hands aiming at shidachi’s right lung.
Shidachi steps with the left foot to the front left and moves the right foot in behind the left, and performs a large makikaeshi to strike uchidachi’s shōmen.
Uchidachi leading with the left foot and shidachi with the right, both sides return to ai-chūdan at the halfway point while displaying zanshin. Lowering the kensen to release the kamae, both sides return to their respective starting position.
The fourth tachi kata is adapted from the second kata of the earlier Butokukai kenjutsu kata, with two major changes. Firstly, shidachi’s initial kamae was changed from seigan to wakigamae to conform with the in’yō-gogyō theory of Ittō-ryū. Secondly, the kesa cut to the neck was replaced with a vertical cut to the head since the neck is not a valid target area in modern kendō.
This form was chosen as the fourth, and first of the technique-oriented, kata because it neatly ties together the three principles taught in the first three kata: distance, centre line, and control of the centre.
In the second Butokukai kenjutsu kata, which served as a template for this form, uchidachi starts in hassō, but hassō had, in a baffling move, been renamed to chūdan, presumably to fit into the ten-chi-jin trichotomy. However, in Ittō-ryū, hassō (or a lower, vertical, version of hassō) is known as in no kamae (陰の構え), and its opposite is wakigamae, yō no kamae (陽の構え). Furthermore, in the gogyō system, hassō is considered the kamae of wood, and its natural counterstance is the kamae of metal: wakigamae. For these reasons, it was natural to decide that shidachi should use wakigamae in reaponse to uchidachi’s hassō.
When approaching into ma-ai, it is explained that the steps are “slightly shorter” than usual. Although this is often explained as uchidachi being wary due to shidachi’s sword being hidden and its length unknown, I believe it more likely that they are just matching the opponent’s steps to meet in the centre1. As for shidachi, they are in hanmi for wakigamae and simply cannot take longer steps.
The distance in the current form of the ai-uchi is strange and difficult to get right. The footwork was inexplicably changed at some point3: although it now says for both sides to step forwards with the right foot, the original text did not specify the footwork for shidachi. In old videos, however, shidachi brings the right foot in line with the left during furikaburi, and steps back with the left during the ai-uchi, effectively remaining in place but backing away from where uchidachi is aiming their cut. This makes much more sense, and the ma-ai will be naturally correct without uchidachi needing to adjust by stepping back afterwards4.
Again, there are those who insist that the distance in the ai-uchi is too far for either side to hit because of uchidachi’s careful approach due, supposedly, to being unable to judge the length of shidachi’s sword. This is ridiculous. Even if you do not know the length of the enemy’s sword, you surely know the length of your own sword. Why would you make a cut that cannot reach, while not knowing whether the enemy can reach you in turn? The cut must be performed with full intent to strike the target, and there is a note to this effect in the manual, emphasising that because the attack is made from a longer distance (tō-ma), it must be performed with more vigour to be effective.
There is an explanatory note in the manual stating that for the ma-ai to work, both sides need to make large cuts, properly stretching out at the point when the blades make contact. The furikaburi is explained as being large enough for the opponent to be visible between one’s arms before the cut. If the distance is too close following ai-uchi, it is uchidachi who needs to step back to adjust the distance, but ideally it should be enough for both sides to go from the outstretched cutting position to chūdan; it is not necessary to reach a distance where only the kensen are touching, but the distance should be somewhat closer (chika-ma).
The ai-uchi in tachi yonhonme teaches the student to see through uchidachi’s attack and boldly respond in kind to break their attack by denying them the centre. It requires good understanding of ma-ai and centre control, and an indomitable spirit that does not retreat from an incoming cut.
Upon reaching ai-chūdan, uchidachi senses an opening to thrust at shidachi’s right lung. Why the right lung, specifically? In the previous kata, the thrust is to the solar plexus, in the centre, and in any event the left lung seems more readily accessible. The manual only says to angle the edge to the right (shidachi’s left), but unlike in tachi sanbonme, merely using the curvature of the blade is not enough to reach the target without moving the hands off the centre line. The answer can be found in the explanation for the second Botokukai kenjutsu kata, where the same technique is used: uchidachi angles the edge to the right because they are pressing shidachi’s blade out of the way with the shinogi to gain the centre, thus positioning the kensen for a thrust to the right side of shidachi’s chest5. Because shidachi does their makikaeshi at the very onset of the thrust, uchidachi will end up inclined forwards with the upper body as the resistance from shidachi’s sword suddenly disappears when uchidachi is trying to push it down and aside.
When performing makikaeshi, shidachi needs to maintain contact between the blades for as long as possible to stay in control, and to step immediately with the left foot to bring the body out of the attack line. Since uchidachi is stepping into cutting distance for their own attack to reach, shidachi needs only move directly to the left. Both hands stay close to the body, and, importantly, the left hand stays in the centre throughout the technique, moving up in a straight line in front of the face and above the forehead. The feeling is one of reeling in uchidachi’s blade while stepping off the line. Using the momentum of uchidachi’s deflected thrust, the kensen is brought around and into furikaburi to cut without pause as the right foot steps in behind the left on a line parallel to the original centre line. At the end of the cut, both feet should be pointing towards uchidachi at an angle of about 30° (“1 o’clock”).
And anyway, the saya would still be visible, giving an upper bound for the blade’s length. ↩
In the Butokukai kenjutsu kata, this is called uchiawase (打ち合わせ), meaning to strike (the swords) together. Ai-uchi (相打ち) normally refers to a mutually killing blow where both sides simultaneously strike one another, so I personally prefer the more precise original term. Perhaps the wording was changed to emphasise that the goal is not simply to bang the swords together, but to make proper cuts to take the centre, leading to kirimusubi. ↩
Seemingly in 1981, with the publication of the modern-language version of the manual. ↩
I lack the authority to write what I think about such changes, so I will instead quote a senior teacher whom I hold in high esteem: “They think they know better than the old masters? Here’s what I think of that: [this word is rated renshi and above] you!” ↩
Sasaki-sensei states that the thrust is actually aimed at the centre, but ends up going towards the right lung because the kensen is pushed aside by shidachi’s makikaeshi. This is possible, but given the background of the seitei kenjutsu kata and the fact that it would be very dangerous to make the thrust while shidachi’s sword is still in the centre, I believe the wording should be taken literally. ↩