Two-stone edge squeeze

White to play  

White to save his group.

Solution  

and form the first part of the two-stone edge squeeze tesuji. Note that is forced, as atari from the other direction leads to the capture of one of the two groups cut apart.(see later) also prevents the atari at a.

Solution  

The throw-in at , which is the second part of this tesuji, forces the capture at . is an atari on three Black stones; White lives if these three stones are captured (see capture three to make an eye).

Solution  

If connects, then after , it's one eye to none. White wins the capturing race.

Black's best defence  

The best plays locally for Black after are successive exchanges, saving the stones: for , for and a for b. As a matter of technique it is often better to not play these exchanges immediately as they can be useful if they are kept in reserve for some time, as ko threats. It's a question of timing. Generally a will not be played before the endgame, whereas and may well be played before the endgame.

Atari at the wrong side  

Giving atari at the wrong side makes it all too easy for White. Not only Black can do nothing to prevent White capturing the stones, but also White can in the endgame capture the stones (by playing at a). But probably a tenuki elsewhere is bigger than this.

Two-stone edge squeeze (Black to play)  

This particular position is also known as the two-stone corner squeeze.

Two-stone edge squeeze (part 1)  

In this capturing race, is necessary to reduce White's liberties. The first part of the two-stone edge squeeze tesuji is the descent at .

Two-stone edge squeeze (part 2)  

The next part of this tesuji is the throw-in at . In this position is yet another good move, if prevents the atari, wins the capturing race.

Variation  

Depending on the condition on the left side, one might argue that is a better move. But it does not change the fact that and capture the key stones.

Black loses the capturing race  

is too slack. Up to , White wins the capturing race by one move.