golearner -- Here's the end of a close game. Playing as White, I lost by 1.5 points! (In other words, at the final count, Black won this game by 1.5 points.) I wonder if I made the right plays, in the right order, or if I need to look earlier... (Actually, I suspect I do - I would have lost by a couple more points if Black hadn't filled in some territory unnecessarily.) Captures prior to this point: Black = 4, White = 12. Based on comments so far, I've tried to evaluate the starting position - that's at the end of this page. (I'm sure I've made some mistakes in values though...)
Harleqin: I think that loses a point, because now the point above is sente for White.
LukeNine45: I think should be at if you're taking gote in the corner there anyway.
golearner: Yeah, I'm not sure there was any value to playing there - I thought that during the game right after doing it...
Harleqin: is unnecessary, losing a point in gote. Black should first play sente at 257, then 2 points gote at 256. is minus half a point in gote. Note that Black could only play here anyway, but now he gets it in sente. Instead, White should play 2 points gote at the left side (where move 253 went).
unkx80: Locally, should be played at White a, Black b, White at . I don't think Black dares to play at c because White d will turn it into a ko. Because after my sequence, Black must connect at d anyway, I will assess the loss of the actual to be 2 points.
Harleqin: loses a point, should first exchange for , then hane and connect. The rest are neutral points.
Harleqin: and are unnecessary, losing a point each. If you were playing by area scoring, then each pass loses a point for black, too.
Dave: I think the first question is whether is sente. If White plays away (e.g. ), what happens after - ?
golearner I've calculated the following - let me know how far off I am!
AREA 1 (top line) - double gote
A, B, C C, V, W, X, A
Area worth 4/2 = 2
AREA 2 (left side) -double gote
D, E, F F, Y, D
Area worth 2/2 = 1
AREA 3 (bottom left) - two parts, first sente, second gote
Part 1 - sente:
Area worth 0 points.
Area worth 1/2.
AREA 4 (line F) - sente/gote
Area worth 1/2? How do you calculate the value when it's sente/gote?
AREA 5 (line L) - Same situation as AREA 4.
AREA 6 (line 6) - sente/gote
Value = 0
AREA 7 (right edge) - gote/sente
O, P, Q, R, S Q, e, O, S
Value = 1/2?
Harleqin: As far as I can see, Area 1 is double sente (see Dave's contribution above). Also, after white C, black V, Black has W as sente, while it is gote for White, so you can assume W is Black's privilege. In your terms:
AREA 1 (top line) - double sente
A, B, C, protect C, V, later Black has W, A
Area worth 4.
golearner: Okay, I think I see that. (I hadn't realized the trouble Dave's idea causes White in the corner.) It looks like area 1 is the hottest area.
Dieter: there is also another point in area 2, so 3 pts double gote, and one more point in 3
golearner: I'm not sure how you're getting the extra points there, unless it's area vs. territory scoring.
Harleqin: Nothing like that. It is just that, if White gets this endgame, Black has to protect again when the outside liberties are filled.
Bill: a is technically White's sente, since it threatens Black's huge group. I think it is worth 9 7/9 points, but I'm not exactly sure. The main thing, as Dave and Harleqin show, is that at this point it is double sente.
b is a gote that gains 1 1/2 points. If White plays there Black will have to fill at z later, as Dieter points out.
Everything else is worth 1 point. c, d, and e are Black sente; f is ambiguous, sort of like White sente; g is a gote that gains 1 point (As unkx80 points out, if Wg Black must later protect around y.).
Bill: First, Black takes the double sente, and then takes his sente.
Dave: Bill, is sente in this situation? Is it possible for White to pick up a point by playing at a? White is 3 points better for having played a, but and d in sente give Black 2 points back. I am thinking of b and c as miai, but I am not sure whether I am correct overall.
Bill: White only gains 1 1/2 points by a gote at a, but gains 2 points by a reverse sente at . However, because of tedomari, I don't think it affects the result. See the alternate play diagrams below.
Bill: White may ignore to take the largest gote with - . Then Black takes his sente.
Bill: Although technically the gote, in the previous diagram, which gains only 1 1/2 points, is smaller than the reverse sente at , which would have gained 2 points, White gets the 1/2 point back because Black gains only 1 point with in this diagram. The end result is the same as the suggested play. By comparison White gains 3 points on the left side but loses 2 points in the center and 1 point on the right side. (The swing points are marked.)
Bill: Your last mistake was 248, which loses 1 point in gote. W246 should have been at 253, but that is unlikely to win. As it was, you gained 8 points against par in this endgame! Thank your lucky stars for that.
Bill: Earlier I said that White's atari at was sente. That means that - is gote. Here is a little about responding to .
(At this point in the game should be at , OC.) But in this situation I think that is the right response to , to avoid worse. (See Dave's diagram.) Earlier in the game the next diagram is normally correct, I think.
Bill: This is the sequence I used to calculate the size of the play. It ends in gote with . (Later - is sente.)