Playing a pro game backwards, Game 1

   

Bill: Picking up on an idea of Holigor's, how about studying a pro game backwards? Instead of 10 moves per page, I think that 30 is reasonable for this game. Given a week or so for comments, we should finish in about two months. Please join in the fun. :-)


[Diagram]
Moves 249 to 258  

Bill: B1 picks up 2 points in gote. Next, W2 is a 2 1/4 point sente. B1 at a (reverse sente) would gain 1/4 point more, but would allow W2 at b, which gains 2 points. But B1 is right, because it is the last play at the 2 level before a significant drop in temperature. See /Tedomari.

White takes several 1 point sente with W4 - B9, and then plays W10, which is an interesting play.




[Diagram]
Moves 259 to 268  



How much does W10 (previous diagram) - W4 gain? See /Bottom side.

Bill: B5 - W10 (moves 263 - 268) are curious. Technically correct is B5 at a, a 1 point sente, leaving a 3/4 point play on the right side. W10 is strange, too, losing 1/2 point. (White gets it back by getting the last play, so the score is unaffected.)

See /Right side.


[Diagram]
Moves 269 to 278  

Black has captured 6 White stones. White has captured 4 Black stones.

Bill: Black gets the last 1 point play (miai value), but it does not matter, because White gets the 1/2 point play. B9 and W10 are miai.



Bill: My source for this ancient game says that the result is jigo, but it looks like a one point win for Black to me. Also, some of the play looks a little funny, as though the players were contesting a point that isn't there. Maybe the game record is not accurate. Or am I mistaken?


John F. There are indeed other versions of this game that give the result as B+1. The original exists only in MS form and that, plus age, opens up lots of possibilities of a corrupted record. There is a perhaps unusual number of jigos in this period, however, and given the circumstances, one must not discount the possibility that any funny moves might be explained by efforts to create a jigo (and if they missed the target they bluffed over the result???).

Bill: Thanks, John.


Pro game backwards, Game 1, moves 219 to 248

Pro game backwards, Game 1, moves 189 to 218

Pro game backwards, Game 1, moves 159 to 188

Pro game backwards, Game 1, moves 129 to 158

Pro game backwards, Game 1, moves 99 to 128

Pro game backwards, Game 1, moves 69 to 98

Pro game backwards, Game 1, moves 39 to 68

Pro game backwards, Game 1, moves 20 to 38

Pro game backwards, Game 1, moves 1 to 19


Funny: just today I found a close concept used in Chess: <[ext] http://en.wikipedia.org/wiki/Retrograde_analysis>.

unkx80: On SL - Retrograde analysis.


Playing a pro game backwards, Game 1 last edited by Bill on May 7, 2006 - 17:52
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