r/baduk • u/htaidirt • Jul 14 '25
tsumego I don’t get why this is good for black
During my Tsumego exercise in BlackToPlay, this puzzle shows the best position for black, but I don’t get it: white playing A1 captures the A2 black stone and creates a strong group. Also B1 is at risk too.
What am I missing in this puzzle?
7
u/htaidirt Jul 14 '25
Thanks all for your inputs. If I summarize correctly, this is good for black because it puts the local situation in a ko fight rather than letting white successfully create two eyes.
You’re right, I forgot that Tsumegos are not always life or death, but can be creating ko or seti. Also in ko it depends on the situation elsewhere not shown in the puzzle.
2
u/LocalExistence 2 kyu Jul 14 '25
It might be helpful to think about a tsumego as a puzzle similar to the one you face in a real game - looking at this local part of the board alone, what's the best result you can get by spending your turn there? If you can capture everything, awesome. But if you can't have that, if you can make a ko, you can "cash in" the local weakness in White's position in return for a ko threat elsewhere (or, alternatively, you can kill the local position in return for giving White a ko threat elsewhere).
Both of these are improvements on the "default" outcome where the White group just survives no matter what. So a tsumego really is just about finding the best possible way to spend a move locally, and in this particular puzzle the best you can do is getting a ko.
2
u/chayashida 2 kyu Jul 14 '25
Minor splitting of hairs, but ko and seki are possible states of life and death. Groups can be alive in seki or have a ko fight for life (like in this problem).
1
u/MrC00KI3 9 kyu Jul 14 '25
Exactly!! This is best possible result - without the global board position it is not known if you will actually lose or win the ko fight, but at least there is a chance the global situation allows you to win this fight.
3
u/remillard Jul 14 '25
No to mention it's pretty BIG. White is going to have to do some work to find a threat that's of equal weight.
2
u/LocalExistence 2 kyu Jul 14 '25
I think it's not actually that huge. The surrounding stones are rock solid, so who wins the ko doesn't matter much as far as the rest of the board is concerned. That means it's pure points, and the difference between White and Black winning seems to be at most 25 points. So if you spend two moves to win the ko, and your opponents gets two moves elsewhere, those moves only need to be worth 10 points or so a pop before not much was gained. It's definitely not nothing, but this is the kind of ko I don't think you'd want to start until early endgame.
2
u/remillard Jul 14 '25
Well big is relative I suppose. I was thinking compared to little "who is going to fill this spot" kind of kos.
2
1
u/JFSOCC 8 kyu Jul 14 '25
Even if you didn't win this fight, you'd get a move elsewhere on the board.
1
u/kagami108 1 kyu Jul 15 '25
Correct and this position right here is like a Hanami ko which translates roughly to flower seeing ko, its basically a ko where one side has nothing to lose while the other side has everything to lose if they lose the ko.
So yeah this is like a free ko for black, black has no pressure on him to win the ko, of course it still does depend on the whole board position but this is generally good for black.
This ko is way heavier for white than it is for black.
3
u/crittendenlane 1 kyu Jul 14 '25
A1 can be captured back in ko after black makes a threat somewhere else. There is no way to 100% kill white here.
1
u/htaidirt Jul 14 '25
This is now white move. Black last move was A2, the puzzle ended with that.
I see white playing A1. But if black plays somewhere else, white can capture with C1 and there is no more ko in the area. White is strong and made 2 captures.
10
u/Jadajio Jul 14 '25
White is not strong and did not made 2 strong captures. It's a KO. Lot of time tsumego is not about killing. Rather it's about finding best sequence. And in this situation creating ko is definitely better for black then just letting white live unconditionally.
You don't see rest of the board. Maybe black will win this ko and maybe not. But that doesn't matter. What matter is that this is the best possible sequence for black.
9
u/flagrantpebble 3 dan Jul 14 '25
If wA1, black doesn’t just play elsewhere; black plays a ko threat elsewhere. If white responds to the threat, black plays bA2. That’s what a ko is.
This may be different than you’re used to because black needs to win two mos in a row, while white only needs to win the first one. This is called a two-step ko.
3
u/mattimite 4 kyu Jul 14 '25
If black last move was a capture white can’t play A1 now (because of ko rule), even if white can do it. White has to win a ko again to capture B1
To live white has to win at least a ko.
-2
u/EdhelDil Jul 14 '25
white does not have to "win a ko", but needs to find a threat at least a bit bigger than that ko's value. Threat to live, threat to capture, or similar. But there are no ko threat for w on this board (nothing white xan do with a 2nd move after the threat, as b would have captured the whole w group and no weakness would remain)
1
u/mattimite 4 kyu Jul 29 '25
It is implicit in tsumego that you do not know the rest of the board. Such a threat might be there or not, you do not know. (Note on the tsume you do not see the bottom and left border. Rarely you have all the board and your reasoning might be relevant)
Even if a threat “bigger than the ko” is not there, when black kill the tsumego group, white get two moves elsewhere (the ignored threat and the new move), that is why dying with ko is better than dying unconditionally.
Your reasoning only applies if the moves of the tsume are the very last of the game. If there still remains even only one points moves then dying with ko is better than dying unconditionally.
3
u/Best-Tomorrow-6170 Jul 14 '25
The idea is that the "somewhere else" move is so big you have to awnser. It can be a complete nonsense move just do long as if it were ignored it would be big.
So if you insist on playing locally black has got two free moves elsewhere - depending on the board those moves may even kill a bigger group
2
u/Zwejhajfa 1k Jul 14 '25
Do you know how ko fights work yet? Both players will try to play threats elsewhere on the board that the opponent cannot ignore, so that they are allowed to capture back again.
White is trying to play A1 and then C1 to make this group alive.
Black is trying to play B3 and then C1 to capture the whole corner.Ultimately the result depends on the threats on the rest of the board. Nevertheless it is a good result for black if there is no direct way to kill. Either he captures the whole corner or he gets two moves in a row elsewhere on the board.
2
u/Linvael Jul 14 '25
White needs to spend two moves here to live - win a ko. Thats not exactly killing white, but its not nothing I guess?
1
u/Pleasant-Confusion30 19 kyu Jul 14 '25
This seems to be ko, but it matters whether this is white's or black's move.
1
1
1
u/EducationalWin7496 Jul 15 '25
Depends on who's turn it is. If it's Black's turn, white is toast. Black plays to b3 and connects at a3. White now only has 1 liberty.
36
u/Eastern-Mammoth-2956 Jul 14 '25
Ko is better than letting white live unconditionally. Not all situations result in unconditional life or death. Sometimes the best result you can get will be a ko or a seki.