Article by Emanuel Giordano 

In most versions of the Gojushiho kata the so-called "drunk step" has disappeared, replaced by a simpler lateral step similar to that of the Naihanchi kata. In the June 2021 article "STUDY ON THE DIFFUSION OF GOJUSHIHO IN THE VARIOUS SCHOOLS" we saw the main differences between the various versions of this kata, including the presence/lack of this technique, as well as how these reached the various Karate schools. When, however, was the drunken step removed, and who made this decision?
To answer this question we need to examine some sources. An important source is Miyahira Katsuya sensei, second president of the Okinawa Shorin-ryu Karate-do Kyokai, who gave a talk on Karate at the Shidokan Shorin-ryu honbu dojo on April 3, 1997. The interview was conducted by the Te Discussion Association (手を語る会), and transcribed in Okinawa Shorin-ryu Karate-do Kyokai's internal magazine published in 2014. The Te Discussion Association is the same one that conducted the interview with Ishikawa Seitoku sensei in 1999, interview quoted in the article: CHIBANA SENSEI'S TODE RESEARCH INSTITUTE. In this speech Miyahira sensei said: 
"[...] in Gojushiho there is a technique called itchadi イッチャーディ (酔拳), but Tokuda Anbun sensei said 'This is already obsolete, so we will change it to a correct position'."
I would like to bring attention to the uchinaaguchi term used by Miyahira sensei, itchadi イッチャーディ. Miyahira sensei explained the meaning using the kanji 酔拳, meaning drunken fist. Since Miyahira sensei also studied Shorin-ryu with Tokuda sensei, and therefore being a direct source, this information would seem to resolve the question, but things are a little more complex than they seem. How could one explain the disappearance of this technique even from the versions of Gojushiho not deriving from Tokuda sensei?! In fact, as we have already seen in the article "STUDY ON THE DIFFUSION OF GOJUSHIHO IN VARIOUS SCHOOLS", this technique is also missing in the versions taught by Yabiku Motoku (source: video from 1951), Toyama Kanken (source: Okugi hijutsu Karate-do, book of 1956), Gusukuma Shinpan (see aforementioned article), Mutsu Mizuho (source: Kenpo gaisetsu, 1930 book) and Soken Hoan (source: original video of the aforementioned master).

Shimabukuro Zenpo (Seibukan Shorin-ryu) performing the drunken step
The answer is quite simple! All of the above, except Soken sensei, learned the kata from Yabu sensei. Yabiku sensei studied at Shihan Gakko from 1905 to 1910, Toyama and Tokuda from 1906 to 1911, Gusukuma (like Tokuda) taught Karate at Okinawan public schools, then under the direction of Yabu sensei, and Mutsu Mizuho learned kata from Yabu sensei during a trip to Okinawa. It is therefore quite clear that while Hanashiro Chomo, Motobu Choyu and Kyan Chotoku continued to hand down the kata with the drunken step, Yabu Kentsu decided to remove it because, as Tokuda sensei said, it was (in his opinion) an obsolete technique. This is yet another confirmation, whenever it was needed, that Yabu sensei was a true innovator, and not a conservative as he has often been described. A master who modified and simplified the kata to be taught at the Shihan Gakko of Okinawa. As for Soken sensei, it is possible that he removed this technique to adapt to the majority of teachers, or due to difficulties in performing it once he reached old age.
Since the majority of versions of Gojushiho practiced today derive from the teachings of Yabu sensei, this explains why this technique is considered rare today. The importance of "sergeant" Yabu in the Karate panorama of the time should not be underestimated! In fact, even some students of Nakama Chozo sensei, who had taught them the version of Gojushiho learned from Hanashiro sensei, therefore with the drunken step, modified the kata by eliminating this technique, fortunately preserved by others.
  • "Shorin-ryu Karate: kata 2" (here)
  • "Shorin-ryu Karate: kata" (here)
  • "Shorin-ryu Karate: The legacy of the bodyguards of the king of Okinawa" (here)
  • "The legend of the masters of Okinawan Karate: Biographies, curiosities and mysteries"  (here)