Small avalanche
Subsequently, to
are all forced. Notice that
threatens to capture the two key white stones in a ladder at x.
The typical response for is at a, possibly leading to the canonical joseki. However, if the ladder is favourable for White, then
can also be played at b.
Table of contents |
The canonical joseki and its variations
This is the canonical joseki for the small avalanche, most often seen in the literature. is the most usual answer, but there are other variations. After
, the
stones cannot be saved, so Black goes for the upper side instead. This canonical joseki is also the simplest small avalanche joseki because both groups are settled.
White has some influence along the left side as well as points on the corner, but Black's thickness on the right is truly impressive, after having captured two stones. Also note that Black's influence is along the upper side, which is typically more important than the left side when White chooses to play the avalanche.
For beginners, it is worth noting that cannot capture the
stone by playing at
, because then Black will capture all the White stones in a connect-and-die with a move at
.
There are cases where White omits in the previous diagram, but they are rare. A likely continuation when Black pulls out with
is shown here. In this diagram Black has played on both sides - the difference from the normal joseki is large.
can also attach as shown here; Kogo's give this variation as a joseki. Note that
is not played at a, so as to allow cutting at b later.
Note that must not atari here, because after
extends,
can only capture the two stones. After
and
, the result is too good for Black - Black is too thick.
If connects at
, then
plays at a and takes the whole corner.
Fighting variations
at the vital point is a strong move which provokes a fight. Up to
there is little room for variation.
The joseki continues with these moves, but the fight is just beginning. The Black group in the center and the White one on the top will have to fight it out afterwards.
White may choose to give atari at a before playing . This will make White b sente, but the value of White c is diminished. Black for his sake, might play d or e instead of
.
is yet another possibility. After
, a, b, and c are all possible continuations for White, and the fight spreads into the center.
Ladder favourable for White
If the ladder towards the lower right corner favours White, then can extend here. Then the sequence here is most common. With
, Black has saved his corner, but still must face the center fight. The continuations are the same as above, but
makes better shape than White a.
may be played at b or c. With
, White will get better endgame benefit if White gets to play at d. With
at b or c, White can get some endgame benefit on the left edge.
The ladder referred to in the commentary to the previous diagram is shown here. White should play this only if the ladder of
does not work.
Charles Matthews: This absolute statement needs to be qualified by a sacrifice variation from Korea. See Jungsuk in Our Time.
If the ladder does work for Black, the only way for White to avoid an immediate collapse is to extend at . However, this is too submissive.
now is enough to capture the corner, and Black's advantage is immediately apparent.
On the other hand, if the ladder favors White, is uncommon. The only joseki for this situation is this one.
Eventually, Black makes a wall towards the top but gives both the left side and much of the corner to White. It was developed in Korea in the late 1980s.
Trick play
There is also a variation where Black plays at instead of a. This is a trick play, but the refutation can be difficult to find. See small avalanche - trick play for more.
Mistakes
In the joseki, should be played at a or b. If
cuts directly, then
captures the two key stones, and typically this means "game over".
See also: