Since we've had a couple of pass incidents this week, now seems a good time to resurrect the greenest and passiest game of them all: the "World's First Environmental Go Game" from 1998.

This was part of a mathematical go experiment run by Prof. Elwyn Berlekamp in California when he managed to get husband-and-wife 9-dan team Rui Naiwei and Jiang Zhujiu ("Jujo") to attempt a game that used 40 cards numbered from 20, 19.5, 19, 18.5 and so on down to 0.5. The players were allowed to take the top card (and say Pass) or play on the board. The final score was equal to score on the board plus the total points on the cards taken, plus 9.5 komi for White.

Elwyn had planned to use Ing rules, but the players (even though Chinese) appeared to use Japanese scoring. The result was said to be B+0.5 by territory (Japanese) scoring, W+2.5 by area (Ing) scoring, which will mean different things to different people but sounds like a possible marital-harmony stitch-up to cynical ol' me.

Our own Bill Spight, a contributor in the research, will, I hope, tell us more about what it all meant in the end, but as I understand it, plans for a follow-up didn't go as, er, planned. Maybe they didn't get enough $100s when they passed Go?

Here it is again, annotated with bonus score counting.
I did it by hand so don't be surprised if there are arithmetic errors.