AGA Rules at Portland Tournament

Two unusual occurrences highlighted details of the AGA rules at the Portland Go Tournament last weekend.

One game involved a seki with points: two black groups, each with one eye, separated by a white group with none. The white group shared one liberty with each black group, which neither player wanted to fill. The Japanese rules give no points in seki, but the AGA rules make no such special exception; black’s eyes are territory. These two points did not affect the outcome of that game.2014.10.22_portland-tourney

A second game was resolved by mathematical proof. At the end of the game, the score was a tie on the board, so white won by the half-point komi. (This was a “one stone handicap” game). Later, black discovered a stone on the floor that he claimed was a prisoner of his. Could it be determined if that stone came from this game? Another player argued that the tie on the board was impossible, given that there was no seki and both players played the same number of moves. Working with several players, the tournament director constructed a proof of this fact. If both players played the same number of moves, the total number of stones on the board (after filling prisoners into territory) must be an even number. Since there are 361 points on the board, the total amount of territory (i.e., the number of vacant points) must be odd. Both players therefore cannot have the same score, so a stone did disappear from this game. White bowed to this logic and the result was reversed.

The tournament was held October 18-19 on the picturesque campus of Lewis & Clark College in Portland, Oregon. 32 players participated.

The winners, from first to third in each division, were:

Open division: Kaichi Suzuki (5-0), Boyang Chen (founding the University of Oregon Go Club), Xudong Zhao
Dan division: Ben Hakala, Maxwell Chen, Troy Wahl
Single-digit kyu division: Daniel Takamori, Sam Levenick (president of the Lewis & Clark Go Club), Robert O’Malley
Double-digit kyu division: Ethan Zhuang (5-0), Roger LaMarche, Vivienne Blandy
Top youth player: Ethan Zhuang
Top female player: Vivienne Blandy

The tournament director wishes to thank Yellow Mountain Imports for a discount on prizes, GoClubs.org for their outstanding tournament software, the Lewis & Clark College Go Club for access to the rooms, and the various volunteers who brought boards, snacks, etc.
– Peter Freedman, TD

photo: Daniel Takamori (left) and Thor Dodson enjoy a bonus game in the 75-degree October sun while waiting for the end of the last round.

 

via American Go E-Journal http://ift.tt/1w5ODZ6

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