{"abstract":"Fragmented positions lose only half the intended penalty.","category":"Go territory scoring","checks":8,"contract":"Input [board, komi_tenths]. Each colour scores stones + empty regions bordered only by it, minus two points per orthogonally connected chain. Return [black, white, margin_tenths] with margin = 10*(black-white) - komi.","contract_signature":"x","evaluation_group":"w2-go-territory-scoring-group-tax","failed_approach":"Exempting each colour first chain still undercharges by two points.","family":"w2-go-territory-scoring-group-tax-tax-rate","id":"FA-83046","implementations":{"attempt":{"sha256":"6b42b0fb56a6eb9544fb8b6dcbf452e51b86a0dbdc2d2bd18022598265cec0f5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    board, komi = x\n    n = len(board)\n    m = len(board[0])\n    score = {'B': 0, 'W': 0}\n    groups = {'B': 0, 'W': 0}\n    seen = set()\n    for r in range(n):\n        for c in range(m):\n            if (r, c) in seen:\n                continue\n            col = board[r][c]\n            seen.add((r, c))\n            stack = [(r, c)]\n            size = 0\n            touch = set()\n            while stack:\n                i, j = stack.pop()\n                size += 1\n                for p, q in ((i - 1, j), (i + 1, j), (i, j - 1), (i, j + 1)):\n                    if 0 <= p < n and 0 <= q < m:\n                        v = board[p][q]\n                        if v == col and (p, q) not in seen:\n                            seen.add((p, q))\n                            stack.append((p, q))\n                        elif v != col:\n                            touch.add(v)\n            if col == '.':\n                if len(touch) == 1:\n                    score[touch.pop()] += size\n            else:\n                score[col] += size\n                groups[col] += 1\n    b = score['B'] - 2 * max(groups['B'] - 1, 0)\n    w = score['W'] - 2 * max(groups['W'] - 1, 0)\n    return [b, w, b * 10 - w * 10 - komi]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[[[['.B.', 'B.B', '.B.'], 65], [1, 0, -55]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], 75], [8, -2, 25]], [[['BBBB', 'B..B', 'B..B', 'BBBB'], 20], [14, 0, 120]], [[['WWW', 'W.W', 'WWW'], 0], [0, 7, -70]], [[['B.W', '...', 'W.B'], 5], [-2, -2, -5]], [[['.B...', 'B....', '.....', '....W', '...W.'], 65], [-1, -1, -65]], [[['BW.', 'BW.', 'BW.'], 75], [1, 4, -105]], [[['.....', '.BBB.', '.B.B.', '.BBB.', '.....'], 20], [23, 0, 210]]], [[[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], 0], [13, 8, 50]], [[['BW.', 'BW.', 'BW.'], 75], [1, 4, -105]], [[['..W', '.W.', 'W..'], 5], [0, 3, -35]], [[['B....B', '......', '..WW..', '..WW..', '......', 'B....B'], 65], [-4, 2, -125]], [[['..WW', '.W..', 'B...'], 75], [-1, -1, -75]], [[['..WW', '.W.B', '.WWW', 'B..B'], 20], [-3, 2, -70]], [[['W..B', 'W...', '.W.W', '.W..', 'W.W.'], 0], [-1, 0, -10]], [[['.W...', 'W....', '.....', '....W', 'W....'], 5], [0, 17, -175]]], [[[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], 75], [8, -2, 25]], [[['..WW', '.W..', 'B...'], 75], [-1, -1, -75]], [[['B..', 'B.W', '.W.'], 75], [0, -1, -65]], [[['W..BW.', '.W....', '......'], 20], [-1, -3, 0]], [[['BBBB', '....', '.W.B', 'BBB.', '.BBB', 'BB.B'], 0], [11, -1, 120]], [[['...', '.BW', '.B.', '...', 'B.B', 'BB.'], 5], [1, -1, 15]], [[['B.B', 'WWB', 'BWB', 'BWB', 'WBB'], 65], [3, 1, -45]], [[['B.WBB', 'W.B..', 'W.WWB', '.WB.B', '.WWWW', '..W.B'], 75], [-4, 7, -185]]], [[[['B.W', '...', 'W.B'], 5], [-2, -2, -5]], [[['B..', 'B.W', '.W.'], 75], [0, -1, -65]], [[['B.B...', '......', '..WWB.', '.WB.W.', 'WWB.B.'], 0], [-4, 0, -40]], [[['.WWBBB', 'WBWB.W', 'BBB.W.', 'BB..BB', 'BWB.B.', 'WWW.WW'], 5], [7, 1, 55]], [[['BBBB', 'B..B', 'W..B', '.WBB', 'WB..', '.B..'], 65], [11, -2, 65]], [[['WWWB.W', 'WB....', 'W.WB..', 'W.BB.W', 'BBW...', '.BB.WW'], 75], [2, 0, -55]], [[['BWB', 'W.W', 'WBW', 'BWB', '.W.', 'BWW'], 20], [-6, 1, -90]], [[['.BBW', '.WB.', 'W...', '....', '....'], 0], [1, -3, 40]]], [[[['.....', '.BBB.', '.B.B.', '.BBB.', '.....'], 20], [23, 0, 210]], [[['B.WBB', 'W.B..', 'W.WWB', '.WB.B', '.WWWW', '..W.B'], 75], [-4, 7, -185]], [[['B..', 'B..', '.B.', '..B', '..B'], 65], [9, 0, 25]], [[['....W.', '...B.B', 'BBBB..', '..B.W.', '.B.B.W'], 75], [5, -3, 5]], [[['..B', '.BW', 'B.B'], 20], [0, -1, -10]], [[['.BB..B', '......', 'B.B.BB', '.BBB..', '.B....'], 0], [20, 0, 200]], [[['W..', '.B.', '.W.', '...'], 5], [-1, -2, 5]], [[['..WW', 'B.WW', 'WBBW', '.WBW', 'WWBW', 'B..W'], 65], [0, 7, -135]]]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"group tax case %d\" % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"9381801b18571199089ac7bda3da003ed27869f12a65222cc9dab346efd9c887","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    board, komi = x\n    n = len(board)\n    m = len(board[0])\n    score = {'B': 0, 'W': 0}\n    groups = {'B': 0, 'W': 0}\n    seen = set()\n    for r in range(n):\n        for c in range(m):\n            if (r, c) in seen:\n                continue\n            col = board[r][c]\n            seen.add((r, c))\n            stack = [(r, c)]\n            size = 0\n            touch = set()\n            while stack:\n                i, j = stack.pop()\n                size += 1\n                for p, q in ((i - 1, j), (i + 1, j), (i, j - 1), (i, j + 1)):\n                    if 0 <= p < n and 0 <= q < m:\n                        v = board[p][q]\n                        if v == col and (p, q) not in seen:\n                            seen.add((p, q))\n                            stack.append((p, q))\n                        elif v != col:\n                            touch.add(v)\n            if col == '.':\n                if len(touch) == 1:\n                    score[touch.pop()] += size\n            else:\n                score[col] += size\n                groups[col] += 1\n    b = score['B'] - groups['B']\n    w = score['W'] - groups['W']\n    return [b, w, b * 10 - w * 10 - komi]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[[[['.B.', 'B.B', '.B.'], 65], [1, 0, -55]], [[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], 75], [8, -2, 25]], [[['BBBB', 'B..B', 'B..B', 'BBBB'], 20], [14, 0, 120]], [[['WWW', 'W.W', 'WWW'], 0], [0, 7, -70]], [[['B.W', '...', 'W.B'], 5], [-2, -2, -5]], [[['.B...', 'B....', '.....', '....W', '...W.'], 65], [-1, -1, -65]], [[['BW.', 'BW.', 'BW.'], 75], [1, 4, -105]], [[['.....', '.BBB.', '.B.B.', '.BBB.', '.....'], 20], [23, 0, 210]]], [[[['..B..', '..B..', 'BBBBB', 'WWWWW', '..W..'], 0], [13, 8, 50]], [[['BW.', 'BW.', 'BW.'], 75], [1, 4, -105]], [[['..W', '.W.', 'W..'], 5], [0, 3, -35]], [[['B....B', '......', '..WW..', '..WW..', '......', 'B....B'], 65], [-4, 2, -125]], [[['..WW', '.W..', 'B...'], 75], [-1, -1, -75]], [[['..WW', '.W.B', '.WWW', 'B..B'], 20], [-3, 2, -70]], [[['W..B', 'W...', '.W.W', '.W..', 'W.W.'], 0], [-1, 0, -10]], [[['.W...', 'W....', '.....', '....W', 'W....'], 5], [0, 17, -175]]], [[[['.W.B.', 'W.WB.', '.WB..', 'WB...', 'B....'], 75], [8, -2, 25]], [[['..WW', '.W..', 'B...'], 75], [-1, -1, -75]], [[['B..', 'B.W', '.W.'], 75], [0, -1, -65]], [[['W..BW.', '.W....', '......'], 20], [-1, -3, 0]], [[['BBBB', '....', '.W.B', 'BBB.', '.BBB', 'BB.B'], 0], [11, -1, 120]], [[['...', '.BW', '.B.', '...', 'B.B', 'BB.'], 5], [1, -1, 15]], [[['B.B', 'WWB', 'BWB', 'BWB', 'WBB'], 65], [3, 1, -45]], [[['B.WBB', 'W.B..', 'W.WWB', '.WB.B', '.WWWW', '..W.B'], 75], [-4, 7, -185]]], [[[['B.W', '...', 'W.B'], 5], [-2, -2, -5]], [[['B..', 'B.W', '.W.'], 75], [0, -1, -65]], [[['B.B...', '......', '..WWB.', '.WB.W.', 'WWB.B.'], 0], [-4, 0, -40]], [[['.WWBBB', 'WBWB.W', 'BBB.W.', 'BB..BB', 'BWB.B.', 'WWW.WW'], 5], [7, 1, 55]], [[['BBBB', 'B..B', 'W..B', '.WBB', 'WB..', '.B..'], 65], [11, -2, 65]], [[['WWWB.W', 'WB....', 'W.WB..', 'W.BB.W', 'BBW...', '.BB.WW'], 75], [2, 0, -55]], [[['BWB', 'W.W', 'WBW', 'BWB', '.W.', 'BWW'], 20], [-6, 1, -90]], [[['.BBW', '.WB.', 'W...', '....', '....'], 0], [1, -3, 40]]], [[[['.....', '.BBB.', '.B.B.', '.BBB.', '.....'], 20], [23, 0, 210]], [[['B.WBB', 'W.B..', 'W.WWB', '.WB.B', '.WWWW', '..W.B'], 75], [-4, 7, -185]], [[['B..', 'B..', '.B.', '..B', '..B'], 65], [9, 0, 25]], [[['....W.', '...B.B', 'BBBB..', '..B.W.', '.B.B.W'], 75], [5, -3, 5]], [[['..B', '.BW', 'B.B'], 20], [0, -1, -10]], [[['.BB..B', '......', 'B.B.BB', '.BBB..', '.B....'], 0], [20, 0, 200]], [[['W..', '.B.', '.W.', '...'], 5], [-1, -2, 5]], [[['..WW', 'B.WW', 'WBBW', '.WBW', 'WWBW', 'B..W'], 65], [0, 7, -135]]]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"group tax case %d\" % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Small rectangular toy boards given as strings of B, W and dot; a bounded teaching model of one scoring or bookkeeping rule, not a complete rules engine or server implementation. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-go-territory-scoring-group-tax-tax-rate","generated_at":"2026-09-29T14:50:18.006944+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Go servers and scoring tools compute this value automatically; a wrong answer changes a game result.","root_cause":"The tax multiplier is one instead of two.","sha256":"19bb4012030c5852366c9af13150be99c61d3a9fd2602ba24cc7d925ce484beb","title":"Group tax charges one point per chain · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":40.417,"exit_code":1,"observations":[{"actual":[3,0,-35],"check":"group tax case 0","expected":[1,0,-55],"passed":false},{"actual":[10,0,25],"check":"group tax case 1","expected":[8,-2,25],"passed":false},{"actual":[16,0,140],"check":"group tax case 2","expected":[14,0,120],"passed":false},{"actual":[0,9,-90],"check":"group tax case 3","expected":[0,7,-70],"passed":false},{"actual":[0,0,-5],"check":"group tax case 4","expected":[-2,-2,-5],"passed":false},{"actual":[1,1,-65],"check":"group tax case 5","expected":[-1,-1,-65],"passed":false},{"actual":[3,6,-105],"check":"group tax case 6","expected":[1,4,-105],"passed":false},{"actual":[25,0,230],"check":"group tax case 7","expected":[23,0,210],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"group tax case 0\", \"actual\": [3, 0, -35], \"expected\": [1, 0, -55], \"passed\": false}, {\"check\": \"group tax case 1\", \"actual\": [10, 0, 25], \"expected\": [8, -2, 25], \"passed\": false}, {\"check\": \"group tax case 2\", \"actual\": [16, 0, 140], \"expected\": [14, 0, 120], \"passed\": false}, {\"check\": \"group tax case 3\", \"actual\": [0, 9, -90], \"expected\": [0, 7, -70], \"passed\": false}, {\"check\": \"group tax case 4\", \"actual\": [0, 0, -5], \"expected\": [-2, -2, -5], \"passed\": false}, {\"check\": \"group tax case 5\", \"actual\": [1, 1, -65], \"expected\": [-1, -1, -65], \"passed\": false}, {\"check\": \"group tax case 6\", \"actual\": [3, 6, -105], \"expected\": [1, 4, -105], \"passed\": false}, {\"check\": \"group tax case 7\", \"actual\": [25, 0, 230], \"expected\": [23, 0, 210], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.874,"exit_code":1,"observations":[{"actual":[5,0,-15],"check":"group tax case 0","expected":[1,0,-55],"passed":false},{"actual":[12,3,15],"check":"group tax case 1","expected":[8,-2,25],"passed":false},{"actual":[15,0,130],"check":"group tax case 2","expected":[14,0,120],"passed":false},{"actual":[0,8,-80],"check":"group tax case 3","expected":[0,7,-70],"passed":false},{"actual":[0,0,-5],"check":"group tax case 4","expected":[-2,-2,-5],"passed":false},{"actual":[1,1,-65],"check":"group tax case 5","expected":[-1,-1,-65],"passed":false},{"actual":[2,5,-105],"check":"group tax case 6","expected":[1,4,-105],"passed":false},{"actual":[24,0,220],"check":"group tax case 7","expected":[23,0,210],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"group tax case 0\", \"actual\": [5, 0, -15], \"expected\": [1, 0, -55], \"passed\": false}, {\"check\": \"group tax case 1\", \"actual\": [12, 3, 15], \"expected\": [8, -2, 25], \"passed\": false}, {\"check\": \"group tax case 2\", \"actual\": [15, 0, 130], \"expected\": [14, 0, 120], \"passed\": false}, {\"check\": \"group tax case 3\", \"actual\": [0, 8, -80], \"expected\": [0, 7, -70], \"passed\": false}, {\"check\": \"group tax case 4\", \"actual\": [0, 0, -5], \"expected\": [-2, -2, -5], \"passed\": false}, {\"check\": \"group tax case 5\", \"actual\": [1, 1, -65], \"expected\": [-1, -1, -65], \"passed\": false}, {\"check\": \"group tax case 6\", \"actual\": [2, 5, -105], \"expected\": [1, 4, -105], \"passed\": false}, {\"check\": \"group tax case 7\", \"actual\": [24, 0, 220], \"expected\": [23, 0, 210], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}