endgame in another nutshell

(cont.)

dedicated to the notorious term double sente.
Double sente means the yose is sente for both players.





What's the size of the endgame in this area?











If white plays first, the sequence is sente for white.




The same goes for black. The difference between this and above diagram is 4 points (marked with the green Xs). We learned that if and endgame is sente for one player and gote for the other, the size is doubled if the gote player gets to play it because the sente player was too stupid to grab it.
As for double sente endgame, both players have the chance to get it for free, so it is hard to calculate the value.* (Someone said that it is worth infinite points.)
However, getting a double sente endgame can give you a psychological advantage. Imagine that your opponent will be all like "oh damn... I should have played that... what if I lose by 2 points now..." and become more overplay-prone.

So much for the theory!





In reality, this kind of endgame is (almost) always more sente for one of the players. White A threatens the black corner (if black blocks once and tenukies, the corner is dead in ko, or alive in ko, whichever you prefer), and black B threatens to ruin white's eastside territory. In a perfect game, whoseever threat is bigger will get the endgame. In a game between two stupid humans, it is the one who is more lucky who will get it.

When you are unsure whether your opponent might tenuki your supposedly sente move (this goes for single sente moves too), there is this rule of thumb (found on senseis):

If you hope your opponent doesn't answer your move, your move is probably sente.



But keep in mind that there are situations where playing endgame too early can be bad.




Feel the power of white's moyo!






And now look how black's moves have increased white's power (in sente).




*The nerdy way to calculate is to assume that everything is gote and calculate the net value of the move and add the half size of the continuation to a gross value, and do that for both sides. However, it is probably easier to do an overall score estimation for every move than calculating that (and see rule of thumb).

endgame thinking in a nutshell

(for the clueless endgame newbies)


Endgame, also referred to as yose, is the end of the game, as the name might suggest. In Go, the value of moves get smaller towards the end of the game. And as the game approaches the end, it becomes possible to express the value of a move in an exact number points.



what's the value of investing a move here?











to count the value of an endgame move, we compare the situation as black plays there and the situation as white plays there. Here black has 6 points and white has 5 points.







and if white plays first, black has 5 points and white has 6.
The endgame is worth 2 points (and for the more advanced, there is also a difference of 3 ko threats).



Since the endgame is gote for both sides, when you try to estimate the score you can add the two triangled stones. It means that both players have an equal chance of getting the endgame. It is pretty accurate, if you want to be more accurate, you'll have to play the endgame to the end in your head.






Next is this situation... Try to take a guess about the value of the yose first.







This situation is different from the previous one since white has to protect at 4. The sequence is sente for black.





If 4 is omitted, bad things happen.


So we learned we have to compare the situation when black plays first to the situation when white plays first. Note that for white, the sequence is gote. The difference in territory is marked by the 3 green Xs. For black, the endgame is sente 3 points. For white it is gote 3 points, which is called reverse sente since it prevents black from playing it in sente. In this case the value is doubled (an approximation for your brain), 3 points reverse sente = 6 points gote.



For score estimation, it is safer to assume that black gets to play his sente sequence.

to be continued