FA-83176 / Go territory scoring / Open access

Exact draws are assigned to one player · case 01

A zero margin is reported as a win.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The winner comparison includes equality.

VERIFIED REPAIR

Report draw when the margin is zero.

Unsuccessful approach: Moving the equality to the white test still awards the draw.

Case contract

Input [size, black_area, komi_tenths] for a board with no dame. White area is size^2 - black_area. Return [margin_tenths, winner] where margin = 10*(black - white) - komi and winner is B, W or draw.

Why this case matters

Go servers and scoring tools compute this value automatically; a wrong answer changes a game result.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    size, black, komi = x
    total = size * size
    margin = 20 * black - 10 * total - komi
    if margin >= 0:
        return [margin, 'B']
    if margin < 0:
        return [margin, 'W']
    return [0, 'draw']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[9, 3, 5], [-755, 'W']], [[9, 26, 65], [-355, 'W']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[19, 184, 70], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[9, 6, 0], [-690, 'W']], [[9, 3, 5], [-755, 'W']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[9, 43, 50], [0, 'draw']], [[19, 185, 90], [0, 'draw']]], [[[13, 163, 5], [1565, 'B']], [[13, 105, 5], [405, 'B']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[9, 43, 50], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[13, 167, 0], [1650, 'B']], [[13, 59, 5], [-515, 'W']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[9, 43, 50], [0, 'draw']], [[9, 42, 30], [0, 'draw']]], [[[13, 107, 65], [385, 'B']], [[13, 136, 5], [1025, 'B']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[9, 43, 50], [0, 'draw']], [[13, 87, 50], [0, 'draw']]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("black count case %d" % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
black count case 0	`[-755, 'W']`	`[-755, 'W']`	Passed
black count case 1	`[-355, 'W']`	`[-355, 'W']`	Passed
black count case 2	`[175, 'B']`	`[175, 'B']`	Passed
black count case 3	`[670, 'B']`	`[670, 'B']`	Passed
black count case 4	`[470, 'B']`	`[470, 'B']`	Passed
black count case 5	`[-635, 'W']`	`[-635, 'W']`	Passed
black count case 6	`[0, 'B']`	`[0, 'draw']`	Failed
black count case 7	`[0, 'B']`	`[0, 'draw']`	Failed

SHA-256 / 5f91e3d376e9ac725ea00e681523f3d615358a4924b231f31c5e468069aaf3cf

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    size, black, komi = x
    total = size * size
    margin = 20 * black - 10 * total - komi
    if margin > 0:
        return [margin, 'B']
    if margin <= 0:
        return [margin, 'W']
    return [0, 'draw']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[9, 3, 5], [-755, 'W']], [[9, 26, 65], [-355, 'W']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[19, 184, 70], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[9, 6, 0], [-690, 'W']], [[9, 3, 5], [-755, 'W']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[9, 43, 50], [0, 'draw']], [[19, 185, 90], [0, 'draw']]], [[[13, 163, 5], [1565, 'B']], [[13, 105, 5], [405, 'B']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[9, 43, 50], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[13, 167, 0], [1650, 'B']], [[13, 59, 5], [-515, 'W']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[9, 43, 50], [0, 'draw']], [[9, 42, 30], [0, 'draw']]], [[[13, 107, 65], [385, 'B']], [[13, 136, 5], [1025, 'B']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[9, 43, 50], [0, 'draw']], [[13, 87, 50], [0, 'draw']]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("black count case %d" % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
black count case 0	`[-755, 'W']`	`[-755, 'W']`	Passed
black count case 1	`[-355, 'W']`	`[-355, 'W']`	Passed
black count case 2	`[175, 'B']`	`[175, 'B']`	Passed
black count case 3	`[670, 'B']`	`[670, 'B']`	Passed
black count case 4	`[470, 'B']`	`[470, 'B']`	Passed
black count case 5	`[-635, 'W']`	`[-635, 'W']`	Passed
black count case 6	`[0, 'W']`	`[0, 'draw']`	Failed
black count case 7	`[0, 'W']`	`[0, 'draw']`	Failed

SHA-256 / eb7bc9a2ff6187e3c759495246755c396328e0a38e3f6fe6254568b3e72e42b0

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    size, black, komi = x
    total = size * size
    margin = 20 * black - 10 * total - komi
    if margin > 0:
        return [margin, 'B']
    if margin < 0:
        return [margin, 'W']
    return [0, 'draw']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[9, 3, 5], [-755, 'W']], [[9, 26, 65], [-355, 'W']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[19, 184, 70], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[9, 6, 0], [-690, 'W']], [[9, 3, 5], [-755, 'W']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[9, 43, 50], [0, 'draw']], [[19, 185, 90], [0, 'draw']]], [[[13, 163, 5], [1565, 'B']], [[13, 105, 5], [405, 'B']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[9, 43, 50], [0, 'draw']], [[9, 43, 50], [0, 'draw']]], [[[13, 167, 0], [1650, 'B']], [[13, 59, 5], [-515, 'W']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[9, 43, 50], [0, 'draw']], [[9, 42, 30], [0, 'draw']]], [[[13, 107, 65], [385, 'B']], [[13, 136, 5], [1025, 'B']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[9, 43, 50], [0, 'draw']], [[13, 87, 50], [0, 'draw']]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("black count case %d" % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
black count case 0	`[-755, 'W']`	`[-755, 'W']`	Passed
black count case 1	`[-355, 'W']`	`[-355, 'W']`	Passed
black count case 2	`[175, 'B']`	`[175, 'B']`	Passed
black count case 3	`[670, 'B']`	`[670, 'B']`	Passed
black count case 4	`[470, 'B']`	`[470, 'B']`	Passed
black count case 5	`[-635, 'W']`	`[-635, 'W']`	Passed
black count case 6	`[0, 'draw']`	`[0, 'draw']`	Passed
black count case 7	`[0, 'draw']`	`[0, 'draw']`	Passed

SHA-256 / 5bd94aebd3e1538e82ad760deaf5140966df6ef6bbeea679b86865d0167270cd

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:50:19.237086+00:00.

Case digest / 519c9b328c494a1479fc14c42c0de99438b62b45fb32744d55b0f1a4127a9cbb