# The theme of this test suite is how to play inside an already living # group to turn potential territory into a seki. A typical example # would be this corner group # # |OOOOOO # |XXXXXO # |..a.XO # |....XO # +------ # # where white can make seki in sente by playing at 'a'. There are also # numerous test cases to check the followup moves to get a seki. In # many cases one or both players have the option to make ko for life # and death of the entire corner (whereby black would get territory # points if winning). Is is generally assumed in this test suite that # white tries to achieve ko while black tries to avoid it, since the # ko in most cases is favorable to white. loadsgf games/seki04.sgf 1 reg_genmove white #? [B2|B1|A2] # B2 also secures life but leaves a much bigger ko threat behind. 2 reg_genmove black #? [A2|B1] play white B2 # Tenuki lets white make ko with A1 3 reg_genmove black #? [B1|A2] play black B1 4 reg_genmove white #? [A2] undo undo play white B1 5 reg_genmove black #? [A2] 6 reg_genmove white #? [A2] play black A2 7 reg_genmove white #? [B2]* undo # White kills through bent four in the corner. play black B2 8 reg_genmove white #? [A2] loadsgf games/seki05.sgf # C2 gives a sente seki, while B1 gives a gote seki. Other moves fail. 101 reg_genmove white #? [C2] 102 reg_genmove black #? [C2|C1|B2|B1] play white C2 # Only B1 and A2 (oddly enough) avoids giving white a ko option. 103 reg_genmove black #? [B1|A2]* play black B1 104 reg_genmove white #? [B2] play white B2 105 reg_genmove black #? [C1] play black C1 106 reg_genmove white #? [A2] play white A2 107 reg_genmove black #? [D1] undo undo play black A2 108 reg_genmove white #? [C1] undo undo undo play black B2 109 reg_genmove white #? [B1] undo play black C1 110 reg_genmove white #? [B1] undo undo play white B1 111 reg_genmove black #? [C2]* undo play white C1 112 reg_genmove black #? [B1]* loadsgf games/seki06.sgf 201 reg_genmove white #? [B2] 202 reg_genmove black #? [B2] # Both A2 and B1 lead to seki. Strictly speaking A2 is a better move # since it leaves black the option to take sente and let white make a # thousand-year ko. For now we accept both. play white B2 203 reg_genmove black #? [A2|B1] play black A2 204 reg_genmove white #? [B1] # White gets a thousand-year ko if black plays tenuki. play white B1 205 reg_genmove black #? [C1|C2] # A1 makes a clean seki with no ko aji. undo play white C1 206 reg_genmove black #? [A1] undo undo play black B1 207 reg_genmove white #? [A2] play white A2 208 reg_genmove black #? [C2] 209 reg_genmove white #? [A3] undo undo undo play white B1 210 reg_genmove black #? [B2] loadsgf games/seki07.sgf 301 reg_genmove white #? [B2] 302 reg_genmove black #? [B2] play white B2 303 reg_genmove black #? [A2|C1|C2] play black A2 304 reg_genmove white #? [C1] # Black can start ko with B1 if desperate. play white C1 305 reg_genmove black #? [C2] play black C2 306 reg_genmove white #? [B1] # Now black can live with territory. undo undo play white B1 307 reg_genmove black #? [C1] undo undo play black C1 308 reg_genmove white #? [A2] # Tenuki is okay. What remains is a double-sided ko threat (0 points # double sente). play white A2 309 reg_genmove black #? [B1|C2|C9] play black B1 310 reg_genmove white #? [C2] undo play black C2 311 reg_genmove white #? [B1] # A2 also makes seki, but costs a prisoner. undo undo undo play black C2 312 reg_genmove white #? [B1|C1] play white B1 313 reg_genmove black #? [C1|A2] play black C1 314 reg_genmove white #? [A2] undo play black A2 315 reg_genmove white #? [C1] undo undo play white C1 316 reg_genmove black #? [A2] loadsgf games/seki08.sgf 401 reg_genmove white #? [B1] # Most moves secure territory but C1 and C2 are most natural. We also # allow B1. 402 reg_genmove black #? [C1|C2|B1] # C1 and C2 both secure seki in sente, but C1 is one prisoner better. # B2 leaves white the option to make ko. play white B1 403 reg_genmove black #? [C1|C2]* play black C1 404 reg_genmove white #? [A2|D1] play white A2 405 reg_genmove black #? [C2] play black C2 406 reg_genmove white #? [D1|E1] undo undo play white D1 407 reg_genmove black #? [C2|E1] play black C2 408 reg_genmove white #? [A2] undo play black E1 409 reg_genmove white #? [A2] play white A2 410 reg_genmove black #? [C2] undo undo undo undo # D1 and A2 also give seki but are one point worse. play black C2 411 reg_genmove white #? [C1] # D1 and A2 are miai to get seki. Black can also opt for a difficult # ko by playing B2, but this is usually not a good idea. Tenuki # suffices for seki and leaves a big mutual ko threat. play white C1 412 reg_genmove black #? [D1|A2|C9] play black D1 413 reg_genmove white #? [A2] loadsgf games/seki09.sgf 501 reg_genmove white #? [B1]* 502 reg_genmove black #? [C1]* play white B1 503 reg_genmove black #? [C1] play black C1 504 reg_genmove white #? [A2] loadsgf games/seki10.sgf 601 reg_genmove white #? [B1] 602 reg_genmove black #? [C1|B1] # B2 gives a hopeless ko. play white B1 603 reg_genmove black #? [C1] play black C1 604 reg_genmove white #? [A2] loadsgf games/seki11.sgf 701 reg_genmove white #? [C1] 702 reg_genmove black #? [C1|B1|B2] play white C1 703 reg_genmove black #? [B2] play black B2 704 reg_genmove white #? [B1] loadsgf games/seki12.sgf 801 reg_genmove white #? [B2] 802 reg_genmove black #? [B2] # C2 is the best way to make seki since it leaves ko aji in black's # favor unless white accepts gote. play white B2 803 reg_genmove black #? [C2] # B1 also makes seki but white definitely ends in gote. play black C2 804 reg_genmove white #? [C1] # After A2 black has the option to start ko with B1, unless white # takes gote and fills at B1. Sooner or later that may be necessary. play white C1 805 reg_genmove black #? [A2] undo play white B1 # A2 is one point bigger than C1 regardless of scoring method. 806 reg_genmove black #? [A2|C1] play black C1 # A3 is one point bigger than A2 under japanese scoring and a half # point bigger under chinese scoring. 807 reg_genmove white #? [A3|A2] undo undo undo # B1 and A2 give gote seki. play black C1 808 reg_genmove white #? [C2] play white C2 809 reg_genmove black #? [B1] # A2 is gote seki and may occasionally be better than allowing black # to initiate a ko. play black B1 810 reg_genmove white #? [A3] # A1 secures seki, removing white's ko aji. play white A3 811 reg_genmove black #? [A1] loadsgf games/seki13.sgf 901 reg_genmove white #? [B2] 902 reg_genmove black #? [B2] # Black probably have more moves to make seki in sente but C2 looks most # natural. C1 is also good enough. B1 suffices to make sente seki as well # but loses one point compared to C2 or C1. play white B2 903 reg_genmove black #? [C2|C1]* play black C2 904 reg_genmove white #? [B3] # B1 gives ko or seki in gote. Tenuki also leaves a seki but compared # to C1 the latter is 1 point double sente. play white B3 905 reg_genmove black #? [C1]* play black C1 906 reg_genmove white #? [B1] # Black can play tenuki and still have seki but since A3 is one point # double sente there is no reason to wait. play white B1 907 reg_genmove black #? [A3]* play black A3 908 reg_genmove white #? [A2] # 1 point double sente, just like 907. undo 909 reg_genmove white #? [A3]* play white A3 910 reg_genmove black #? [A1|A2] # One point to pick up the A1 stone under Japanese rules. play black A1 play black C9 911 reg_genmove white #? [A2] # After white C1 black can make ko with A2 or seki in gote with D1. undo undo undo undo undo play black B1 912 reg_genmove white #? [C1] # White C1 was a mistake. Black makes life with territory at B3. undo undo play white C1 913 reg_genmove black #? [B3] # Black should play B2. A2 and B1 leave an unnecessary ko threat. loadsgf games/seki14.sgf 1001 reg_genmove white #? [B2] 1002 reg_genmove black #? [B2] loadsgf games/seki15.sgf 1101 reg_genmove white #? [D1]* 1102 reg_genmove black #? [C1|C2|D2]* play white D1 1103 reg_genmove black #? [E2] play black E2 1104 reg_genmove white #? [B1]* play white B1 1105 reg_genmove black #? [C2] play black C2 1106 reg_genmove white #? [C1] loadsgf games/seki16.sgf 1201 reg_genmove white #? [B2] 1202 reg_genmove black #? [B2] # Black can make seki in sente with most moves but B1 and A2 lose one # point. Tenuki let's white kill with ko. play white B2 1203 reg_genmove black #? [C2|B3|C1|A3] # B3, A2, and A1 fail to make seki. play black C2 1204 reg_genmove white #? [B1|C1|A3] # A3, B3, and A2 all make seki, but B3 and A2 lose a point. play white C1 1205 reg_genmove black #? [A3]* play black A3 1206 reg_genmove white #? [B3|A2|B1] play white B3 1207 reg_genmove black #? [A2] play black A2 1208 reg_genmove white #? [B1] undo undo play white A2 1209 reg_genmove black #? [B3]* play black B3 1210 reg_genmove white #? [B1] # A3 gains a point compared to A2. B1 is two points worse. undo undo undo play black B3 1211 reg_genmove white #? [A3] # A3 gains a point compared to B3. B1 is two points worse. undo play black A2 1212 reg_genmove white #? [A3] play white A3 1213 reg_genmove black #? [B3] play black B3 1214 reg_genmove white #? [A1] undo undo undo undo # Tenuki leaves seki but loses a point. play white B1 1215 reg_genmove black #? [C1|A3|B3|A2|C9] # B3 and A2 both fail. play black C1 1216 reg_genmove white #? [A3] # A2 also gives seki but loses a point, as does tenuki. play white A3 1217 reg_genmove black #? [B3]* undo undo play black A3 1218 reg_genmove white #? [C1] # Tenuki is fine. play white C1 1219 reg_genmove black #? [B3|A2|C9] undo undo play black B3 1220 reg_genmove white #? [A2|A3]* undo play black A2 1221 reg_genmove black #? [B3|A3] # B1 and B3 lose a point. undo undo play white A3 1222 reg_genmove black #? [C1]* play black C1 1223 reg_genmove white #? [B1] # Only A3 works. If black gets both C1 and A3, white can't do anything # with two stones (in addition to B2). undo undo undo play black C1 1224 reg_genmove white #? [A3] play white A3 1225 reg_genmove black #? [B1|C2|B3] play black B1 1226 reg_genmove white #? [C2] play white C2 1227 reg_genmove black #? [B3]* # C1 is one point better than C2 and A3. undo undo undo undo play black B1 1228 reg_genmove white #? [C1]* loadsgf games/FSGCBot-dr.sgf 234 2010 reg_genmove white #? [A19|B17] loadsgf games/seki_nakade1.sgf 2020 dragon_status D9 #? [alive] loadsgf games/seki_nakade2.sgf 2030 dragon_status F9 #? [critical H9 H9]* play white H9 play white H7 play white G7 play white G9 2050 dragon_status G8 #? [alive]