The New Fuseki (Shin Fuseki is the Japanese go term) was the explosive exploration of new center, side, and non-traditional corner strategies in Japanese professional Go in the mid-1930s, formulated in the book "Shin Fuseki-ho" published in 1934. It was the culmination of a great deal of dissatisfaction on the part of especially the younger pros with an excessive codification of Go in the early 20th century in Japan. Basically too much emphasis had been put on the idea of there being a "sure win" for Black (see komi). The proper demonstration of this sure win was thought to be by perfecting the classical style of Go epitomized by Shusaku, Shuwa, and the other greats from the golden age of the 19th century.
(The Western chess world went though a strikingly similar revolution, called hypermodernism, that started a few years before Shin Fuseki and continued through the same period, which was also around rethinking of the center.)
There is a good deal in writing about the beginning of the New Fuseki era. See the various background materials on Go Seigen , Kitani Minoru and also Yasunaga Hajime, who coined the term. The fact is that the experimentation had begun (undoubtedly had never stopped) by many people. However, there is no doubt that what caught the public and professional imagination (whether in admiration or rage depended on the observer) was the systematic introduction of some weird and flamboyant fuseki by Kitani and Go in the autumn Oteai (the professional rating tournament in Japan) in 1933. It had the best possible justification as Go finished first and Kitani second in the tournament.
(Note: some of John Fairbairn's rough draft translations of material on the Shin Fuseki have been posted at Shin Fuseki Post)
The New Fuseki Era Begins!
Kitani 5p (White) vs Hasegawa 5p 1933-10-1,2
In "Shin Fuseki No Shinro" Kitani mentions in the notes to this game that he tried out his new strategy in two earlier newspaper games (against Maeda and Onoda) but lost both times. I guess it doesn't deserve a new name until it's a winner.
Go Seigen 5p (White) vs Kosugi Tei 4p 1933-10-10,11
Go Seigen himself had started playing 3-3 as both Black and White during the spring and summer of 1933. Here it is his opponent that trots it out in conjunction with tengen. This game, played just days into the Oteai schedule shows dramatically that interest in and acceptance of change was more widespread than legend indicates. The role of Kitani and Go was not so much to invent New Fuseki but rather to serve as its most popular standard bearers.
It is hard to imagine an opening further removed from classical fuseki than this one. The continuation of this game is given and discussed at the end of Fairbairn's second message (Shin Fuseki-Ho).
This game was named the Sixteen Soldiers game.
Honinbo Shusai (White) vs Go Seigen 1933-10-16, 1934-1-29
Just five days after the game above was played, the famous game between Shusai and Go began. Suddenly it was a confrontation not only between generations but between entire eras. The classical age was giving way to the modern - but not without a fight.
At this point Shusai had seen enough for one day and play was suspended. Ultimately the game extended over 14 playing sessions with weeks of analysis in between.
-- Dave Sigaty
hnishy: The website of the inn where Kitani stayed for pondering over the concept shows the Birth of Shin Fuseki monument and other photos. According to the site, Kitani's wife Miharu was the first daughter of the inn owner.