(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[6.50]
CP[Antti Törmänen]AW[ck][cl][cm][bn][dn][do][bp][cp][dp][ep][eq]AB[ci][cj][ej][bk][dk][dl][dm][cn][en][eo][go][fp][cq][dq][fq][er][fr]TR[bk]C[Black has just played the triangle-marked stone. How should white respond?]
;LB[bl:A][bm:B][br:C]C[White A seems like the obvious move – after all, if white doesn't prevent black B, then the white group will die.

Stronger players, however, will also think of white's response of C. Before we start reasoning which move is better, let us see the possible futures of this local position.]PL[W]
;W[bl]C[Option 1: white responds directly]
;B[al]
;W[co]LB[bj:B][br:A]C[The local position is now fairly fixed. There remain two fairly big endgame moves at A and B (from white's point of view), and so white can be sure to get one of them if he wants.]
;AE[al][bl][co]AB[cn]PL[W]
;W[br]LB[bk:A]C[Option 2: white resists

B2 would be called a 'resisting' move, because white is not simply playing out the moves laid out by black A; rather than simply respond, white is advancing the local exchange further.]
;B[bq]C[If black follows white's lead...]
;W[aq]
;B[cr]
;W[cs]
;B[dr]
;W[bl]
;B[al]
;W[co]TR[aq][bq][br][cr][dr][cs]C[...White will then go back to live with his group. Now white has made a good exchange in the corner, as the six triangle-marked stones effectively remove any potential territory black had.]
;AE[al][bl][co][aq][bq][cr][dr][cs]AB[cn]PL[B]
;B[bm]C[Therefore, black will also decline to follow white's lead, and will advance the exchange further.]
;W[co]
;B[bl]
;W[bq]LB[cn:B][dr:A]C[The exchange is now over. There are two endgame moves left locally; the fairly big cut of A, and the much smaller connection of B (from white's point of view).]
;AE[bl][bm][co][bq][br]AB[cn]LB[bl:A][br:B]C[Now the question is: of the two outcomes we saw earlier (starting from either white A or B), which is better? Think a bit before scrolling ahead!]
;LB[bl:A][br:B]C[It turns out that endgame theory does not strictly tell us which of A and B is better. If we wanted to, we could spend a lot of time counting the exact values of white A and B, and their difference would come to less than one point – but this would hardly be feasible unless white had a lot of time (and maybe a pen and paper) at hand. Even then, the answer would depend on the whole-board position, so we should prefer a faster way of choosing that gets us reasonable close to the right answer.

Usually, how strong players do this is by generating a kind of story for what is happening.]
;PL[W]
;W[bl]C[Strong players will generally feel a bit bad about responding with b8. The reason is–]
;B[al]
;W[co]C[– that assuming we get to this result –]
;W[bj]C[– and later in the game white ends up cutting at b10 –]
;B[bi]
;W[ak]LB[bk:A]TR[al][co]C[– now, in this shape, white will eventually need to fill his own territory at A. The triangle-marked stones have become a good exchange that nets black a free point.]
;AB[dc][ec][de][eg]C[If the black upper-left corner instead looked like this –]PL[W]
;W[ai]C[–when we take into account white's privileged endgame –]
;B[ah]
;W[bk]
;B[bh]LB[aj:A]C[– which will look like this, assuming that white has enough ko threats to force b12 (which will usually be the case) –]
;AE[ak][al][bl][co]AW[aj]AB[cn]LB[ah:5][bh:7][ai:4][bi:2][aj:6][bj:1][bk:3]C[– comparing to if white got to play the local endgame at 1 first, white has 1 1/3 points more in this scenario than if black got to exchange b9 first.]
;AE[ah][bh][ai][aj][bk]LB[bi:2][bj:1]C[If we want to optimise white's result even more, then white would like to simply exchange 1–2 and then play elsewhere.]PL[B]
;B[bk]C[Now, if black captures –]
;W[bl]
;B[aj]LB[al:A][co:B]C[– the A-B exchange is no longer a 'free point' that black gets, because black has taken gote once with a10. Now the A-B exchange is black's added value for spending a move turn at a10, and this is fine: strong players hate to give things away for free, but if the opponent paid (in this case, a move) for their profit, that is no problem.]
;AE[bi][aj][bk][bl]AW[bj]LB[bi:B][bj:A][bk:C][al:E][bl:D][co:F]C[Since white A for black B could be thought of a 'free gain for white' – black might consider the alternative C-D-E-F sequence his privilege – black will actually feel inclined not to respond with B. However...]
;W[bi]C[...white might then have a strong follow-up, depending on the surrounding positions.]
;B[bh]
;W[bg]
;B[ah]
;W[ch]
;B[cg]
;W[dh]
;B[bf]
;W[dg]
;B[cf]
;W[ei]
;B[dj]
;W[fi]C[White's getting a living group at around f11 could well be annoying for black if black also had a centre moyo brewing up.

Therefore –]
;AE[bf][cf][bg][cg][dg][ah][bh][ch][dh][bi][ei][fi][dj]AB[bk]LB[bj:A][bk:B]C[– black's correct response to white A is actually the cut of B.]PL[W]
;W[bl]LB[bg:C][bh:B][ai:D][bi:A]C[Now black can play elsewhere. White A, black B, and white C no longer work, as black gets to play the atari of D in sente, preventing the C stone from linking up.]
;AE[ec][de][eg][bj][bk][bl]AW[dc][ce][cg]C[The situation is again totally different if the upper-left corner belongs to white, rather than black.]
;AW[bj]AB[bi]LB[bf:D][ag:C][bi:B][bj:A]C[Now the A-B exchange actually makes a loss for white, as black B gives black follow-ups such as the small monkey jump of C and the placement of D.]
;AE[bi][bj]TR[ci][cj][ej][dk]C[The surrounding black shape also matters to the local endgame. These triangle-marked black stones actually make up a strange shape that would probably never come up together with the upper-left corner white position.]
;AE[ci][ej]AB[dj]LB[dj:A]C[If black had the solid connection of A instead, that would again change the local endgame.]
;B[bk]C[Now, when black plays the hane...]
;W[bl]C[...White is more inclined to respond with b8. This is because –]
;B[al]
;W[co]
;W[bj]C[– later, the value of cutting at b10 will be bigger.]
;B[bi]
;W[ak]LB[ci:A]C[Black is left with a potentially valuable cutting point at A.]
;AE[dc][ce][cg][bi][bj][dj][ak][al][bl][co]AW[fo][go][hp][jq][lq]AB[ci][ej][bk][fm][cn][hr]LB[br:A]C[This game, again, would be totally different. Now white would be inclined to play A as early as possible, as it would affect the lower-side black group's eyes.]
;AE[fm][fo][hp][jq][lq][hr]AB[go]LB[bk:C][bl:A][br:B]C[As we can see, the question of 'which is better, A or B' is a complicated question that refers a lot to the surrounding position.

On the other hand, the surrounding factors are what actually make the decision easier for white to make, as they give hints on how to value the possibility of capturing C, and maybe taking away black's corner territory (and eyes) with B.]
;LB[bl:A][br:B]C[Until now I've waved my hands around a lot about how to think about the choice between A and B while avoiding actually answering. So, what's the deal? Provided that the surrounding positions (such as the upper-left corner) don't really affect the choice, and the rest of the board is reasonably filled up so that there are no extremely big moves remaining, what should white do – A or B?


]PL[W]
;C[Even if most of the board is fairly stable, there is still one key question that we should keep in mind. It is surprisingly easy, too: do we want sente or not?

Usually in go, players want to take sente, handling a local position flexibly and effectively while also keeping the initiative, getting to play in another part of the board first.

However, as the value of sente decreases – this always happens in the endgame, but sometimes also in the middle of a game – it can sometimes be better to instead optimise a local result territorially while letting the opponent play elsewhere first.

White in this position cannot get sente, as he is strictly on the defensive. However, there is an endgame-technical aspect to this problem that relates to sente.]
;W[bl]
;B[al]
;W[co]LB[bj:B][br:A]C[In this result, there are strictly two big moves left: A and B (from white's point of view). If there are no moves elsewhere in A and B's size category – or an even number of such moves – that increases the odds of white getting to play a local tedomari, i.e., the last big move of a certain move size category. On the other hand, if there is an odd number of moves of similar size to A and B, then black will get the tedomari and make a profit. ]
;AE[al][bl][co]AB[cn]PL[W]
;W[br]
;B[bm]
;W[co]
;B[bl]
;W[bq]LB[cn:B][dr:A]C[This end result, on the other hand, has the clearly bigger move of A and then the clearly smaller move of B available. If there is only one notably big endgame move elsewhere on the board, so that white gets to play either it or A, then this outcome is efficient for white.]
;AE[bl][bm][co][bq][br]AB[cn]PL[W]
;W[bl]C[If the rest of the board is completely played out, that brings us back to b8, since it leaves black with exactly two similarly good moves. Now both players will aim to play in a way that always leaves two moves of similar size on the board.]
;B[al]
;W[co]
;B[bq]C[Then the play continues like this, and –]
;W[bj]LB[bi:A][am:B]C[–white will exchange b10 for A, thus preventing black's endgame move of B –]
;B[bi]
;W[aq]LB[ak:A][ap:B]C[–before switching to the corner. Playing A instead would give black the tedomari of B.]
;B[ar]
;W[ap]LB[ak:B][br:A]C[If now black plays A, white B is tedomari, so –]
;B[aj]C[– black further advances the exchange – ]
;W[br]
;B[cr]
;W[as]
;B[an]C[–fighting to get every point possible –]
;W[cs]
;B[dr]
;W[bm]
;B[am]
;W[ao]
;B[ak]
;W[ar]
;B[ds]
;W[bs]C[– until the game is finally over.]
;AE[bi][aj][ak][al][bl][am][bm][an][ao][co][ap][aq][bq][ar][br][cr][dr][as][bs][cs][ds]AB[cn]C[Although it is also important to know how to value different common endgame moves, we see that it is possible to play a strong game also purely by shape knowledge, as long as one understands the meaning behind every move played. Endgame, too, can be fun and be played by gut feeling!])
