Strange things happen at the one-two point
The 2-1 points have some peculiarities; and the heuristic principles of fighting, which normally apply to the sides, often work differently in the corner.
One reason is the impossibility of approaching a 2-1 point from the corner side. This can give the player who occupies the 2-1 point an additional tempo to win a capturing race.
In this case Black wins.
White wins.
Here Black cannot attack from either side because of shortage of liberties.
Another feature of the 2-1 point is the possibity of a throw in tesuji. An example is considered at Stupid Moves.
I will show another example.
Black played as a ko-threat. I will not discuss whether this was the best threat. White answered at
giving Black another threat at a. White should have played at a.
Here was in answer to
. In fact it also attacks
; and is a direct threat.
The throw-in , at the 2-1 point, captures
, because of the weakness at a.
Actually I can point to a stupid player with White who lost a ko because of this mistake. It was a certain HolIgor (IGS 5k*).
Thank you for correcting mistakes.
The 2-1 point is a place where many kos happen. For example, the ko that HolIgor (IGS 5k*) lost.
Black plays hoping for White's mistake. White sees the ko. White suspect that she wins the capturing race without ko (but it is so difficult to read 8 moves ahead, shame on her!), and she decides to fight the ko.
But the sad story of White's mistake has little to do with the topic, and the topic of this page is the 2-1 point. By taking it, Black got a ko that saved his group.
How is this a capturing race? After black's play at the 1-2, wouldn't white make life by:
or
-- Malweth
The 2-1 point is a critical point in many life and death problems. The difference between living or dying locally is at least 20 points. It is something that cannot be taken easily. That's the difference between winning and losing, or losing and losing badly.
Examples
See also: