30
A duchess in London once famously remarked that a man seen on a bus after the age of 40 had obviously failed in life. Confucius perhaps thought that a man not seen in his own chariot by the age of 30 had not "established" himself (而立 jiritsu).
Thirty can be a strange age in go. If you have made it before then, you will have probably had the guns of the matchmakers trained on you and had you married off. And everybody knows what that does to your results!
If you haven't made it yet, of course, 30 can seem like a watershed. But is that just a symptom of the modern age? Fujisawa Kuranosuke was 30 when he became the first ever 9-dan, ahead even of Go Seigen and Kitani Minoru, in the more leisurely days of 1949. The game that is usually reckoned to have earned him this exalted status was against Sakata Eio on 8 June (a sort of mimic go, incidentally).
However, this reckoning excludes his unfinished "Tokatei" game against Hasegawa Akira in 1947 and a default win. The definitive game by the other reckoning was against Maeda Nobuaki in May 1949). He had to score an average of 75 Oteai points over 26 games, but in this now accepted interpretation the run was extended to 28 games.
It was not unknown for a player to reject a promotion by refusing to accept points earned through defaults. The classic case was when Kato Shin became the first player to be entitled to 8-dan in 1939, through winning a game defaulted by his opponent and arch-rival, Suzuki Tamejiro 7d, who was older. Suzuki feigned sickness to avoid seeing Kato promoted. But Kato rejected it (though he did go through the nigiri procedure, was given White and then the game; apparently, though, the game was eventually played and Kato lost). Kato eventually earned his promotion in a way he thought fitting in March 1942. Suzuki was then given 8-dan by recommendation at the same time, by one account, though Iwamoto Kaoru says Suzuki did not become 8-dan until 1943.
So egotism and machismo were a known part of the mix, but the Tokatei incident was obviously something special. In the 1949 Oteai season, Fujisawa played mimic go in all his games as White. He came under pressure to give it up but refused as it was in no way against the rules. It is not clear why his game against Hasegawa was left unfinished except that it was connected with this dispute. Hasegawa, born in 1900, was one of the senior pros, and had also played a major part in restoring the Nihon Ki-in after the war (this included finding venues to replace the burnt-down Nihon Ki-in and the Tokatei Inn was one of them). It is easy to imagine that he got on his high horse and took umbrage when the young whippersnapper Fujisawa refused to back down on mimic go.
So we can infer that while young Fujisawa had "established" himself at age 30 - indeed he was at the summit of the go world - he had yet to learn what duties Heaven required of him and how to indulge himself without upsetting other people.
The position below is the start of his game with Sakata. We call it a "sort of" mimic game as the mimicry does not extend very far. It usually went on much further in his games.
Fujisawa kept on playing mimic go as White, with or without komi, until 1976. A full exposition of his views and details of many other mimic go games are on the GoGoD CD.