In the 1960s the Nihon Ki-in began a campaign to woo newcomers to the game in Japan by using 15x15 boards. Small boards were not a new idea, of course, but the usual sizes used had been 11x11 and 13x13, though 9x9 was not unknown either. Actually 11x11 can probably claim priority, as before World War II Murashima Yoshinori 6-dan and Nakagawa Arata 5-dan published a book called First Steps in Go which used this size. It had a cardboard board and stones attached as an appendix, with a 19x19 grid on one side and 11x11 on the other. It may have been a notable publishing feat, but 11x11 did not catch on.
After the war, Kido (1948, No.10), which was then under the editorial guidance of Murashima, tried again but with 13x13, though exclusively for endgame problems. Igo Club copied the idea and extended it to endgame problems on 11x11 as well. Both sizes have remained popular for that specific purpose ever since.
The Nihon Ki-in later tried again using 11x11 for beginners in ordinary play, but that still did not catch on.
These ultra-small sizes may work well with displaying the tactics of the game, but are weak in showing how much strategy go has. After some later investigation in the mid-1960s, it was found that 15x15 allows beginners to play a game that looks and feels like the real thing in almost all respects.
There were also the practical points that it was, and still is, possible to get 15x15 boards and stones ready made for renju, and that it was possible to fit in a complete game in a typical salaryman's lunch break. (Not to mention the other practical point that a small board is a lot cheaper!)
The 15x15 campaign foundered as well, but during the main push there was an interesting event centred on Chikurin - the duo of Otake Hideo (left, then 6-dan) and Rin Kaiho (right, 7-dan) who were increasingly coming together in battles for supremacy on 19x19. Chiku and Rin are readings of abbreviations of their names, giving a word - Bamboo Grove - that appeals greatly to the Japanese ear. It was widely used at the time.
Under the aegis of Kido, this pair got together and played some practice games on 15x15, initially to get used to the new size and then to assess the komi. At the time both 4.5 and 5.5 were current on 19x19 boards, although there were already amateur voices clamouring for 6.5. Otake eventually suggested 7 points might be right on 15x15, and so the pair then set to a proper game for publication with a commentary. That is what we are presenting here.
Otake and Rin also thought, incidentally, that the proper equivalent of a 9-stone handicap on 15x15 was five stones. A three-stone handicap on 15x15 felt, to them, about equal to six stones on 19x19. To forestall the equivalent of what must be one of the commonest questions in go ("Where are the handicap points on a 9x9 board?"), their 15x15 board had five handicap points, at the 4-4 points and the centre.