Nadare jōseki
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| Black move at 'a' leads to the small avalanche (konadare) and at 'b' to the large avalanche (onadare). |
The avalanche joseki (nadare joseki in Japanese) is one of the most celebrated joseki in the opening stage of the game of Go, and the one that has seen the greatest development in contemporary professional go. Hundreds of unique variations have appeared in high-level games. This is not yet as many as the 1000 lines attributed to the taisha joseki, traditionally thought of the most complex joseki developed in Japan; but the nadare fits much better with current ideas on opening strategy and is often used, while the taisha has been quite unfashionable for a generation.
The avalanche occurs after the moves 1. 3—4 2. 5—4 3. 5—3 4. 4—4. The moves 5. 4—3 6. 3—5 then always follow (image at right). There is then a five-way choice for the next play. 7. 6—4 leads to the small avalanche (konadare) and 7. 6—3 to the large avalanche (onadare).
The origins of the avalanche joseki in professional play can, unusually, be fairly accurately tracked down (most go openings are not so much invented as emerge from casual games into prominence when they are used in a high-profile match, and tournament game records are not always published). In games from 1927, three years after the founding of the Nihon Ki-in, it was adopted by Kitani Minoru, then aged 18, from one of his opponents. Kitani played it in a number of games and developed some first variations of the konadare.
A reason can be given for the lack of previous use in professional play of the nadare. The fourth play goes against a fundamental idea on good shape. Namely, that the two stones at 5—4 and 4—4 find themselves immediately in the formation called hane at the head of two stones, as soon as 4—3 is played by the opponent. This is, generally speaking, a compromised shape; it is almost instinctive for a strong player to see that the konadare line leads to tactical chances. As it happens there is sufficient dynamic compensation for the line to be, not only playable, but also preferred in some kinds of positions —it depends very much on the way the rest of the board looks— the basic reason being that it gives a formation facing in a different direction from that after 4. 6—3, the more common play here.
The invention of the nadare preceded by half-a-dozen years the period of experimentation called shinfuseki. There are some connections, in that shinfuseki was also concerned with sharper plays that relied for their effect on outward influence (and Kitani was a leading figure).
The onadare is the most complex line of all: the konadare can lead to a running fight, but tends normally to force the issue into settled formations. The new move found by Go Seigen in 1957, in a Saikyo Tournament game against Takagawa Kaku, is probably the most famous joseki innovation since the 'secret weapon' plays in the taisha of the early nineteenth century. It occurs at play 13 of the onadare, and Go Seigen's uchimagari (turn inside) set off the modern intensive research in this joseki. It allows the first player to take the corner territory, and usually leads to a complex large-scale fight in the centre.