We last time saw the following common shapes:
- Nobi, tobi and nikken-tobi
- Keima and Ogeima
These shapes use stones of only one color. We will see in this article shapes that only exist thanks to the relationship between white and black stones. These shapes are:
- hane and double hane
We will also discuss a joseki where these shapes appeare.
Hane and double hane
Hane occurs when white (respectively black) bumps "at the head" of a group of black (respectively white) stones as shown in the diagram below. Here white plays with move 1 at the head of the two marked black stones:
This move is very powerful! Indeed, the direction of play of black is imposed by white. In this example, black is pushed to the edge. To draw a parallel with real life, it's as if you were in an uncomfortable position. Two choices are usually available to you: to fight at the risk of making everything go wrong, or to accept and wait for a better opportunity. And the choice is not unique, but depends on the situation you are in. Black has only two possible choices here, playing in A, cutting the white stone and fighting, or playing hane in B, letting himself be pushed to the edge and waiting for a better opportunity.
He can also do nothing locally by doing tenuki and play elsewhere or do hane in C. The interactive example below illustrates the possible repercussions of the different cases mentioned.
Double hane is, as its name suggests, two successive hanes. In the figure below showing the previous example, white made a hane with move 1, then black answered in 2 with a hane and white made a hane on black stone 2 with move 3.
This time, white wants to push as much black as possible towards the edge and confine it to the corner! But it leaves a weakness. Black can look at the atari with 4, white connected in 5 then black cheek 6 to capture the white stone 3:
That's actually what white wanted all along. Now he can play move 7 on the diagram below and sacrifice the white stone. Black takes the stone with 8 and white takes the two black stones in the corner.
Tous ces échanges forment un joseki : blanc conserve le coin et noir a constitué un ponuki (la forme des quatre pierres noires sur le bord droit). Le ponuki est une forme solide car elle donne déjà un œil sur au groupe noir ! De plus, les deux pierres noires dans le coin conservent un peu de potentiel. Noir pourrait peut être les réutiliser plus tard dans la partie. On dit alors que ces deux pierres conservent de « l’aji », ou potentiel.
This exchange well the strength but also the weakness of the double hane. This shape allows to put a very strong pressure on the opponent's stones, but it has a weakness that must be taken into account before making a move.
Crosscut is the shape taken by two black and two white stones that intersect, represented by the numbered stones in the following figure:
This form is closely related to hane, because it results from a cut after a hane at the head of a stone. Black comes to the contact of the white stone with 1, white with hane with 2 and black cut in 3: crosscut!!!
The crosscut has many uses depending on the situation in which it is used. It is generally used to cut a group of opposing stones in two or create a base of life for one of its groups of stones.
The consequences of hits after a crosscut can become complicated. To see the possible sequences of moves, you can navigate in the example below: