FA-83166 / Go territory scoring / Open access

Black-only counting assumes 361 points on every board · case 01

Small-board games are scored against the 19x19 total.

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

ROOT CAUSE

The total point count is hard-coded.

VERIFIED REPAIR

Use size*size intersections.

Unsuccessful approach: Counting (size-1)^2 squares instead of intersections still undercounts the board.

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 = 361
    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, 13, 65], [-615, 'W']], [[9, 72, 5], [625, 'B']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[9, 27, 75], [-345, 'W']], [[9, 6, 0], [-690, 'W']]], [[[9, 80, 70], [720, 'B']], [[9, 64, 0], [470, 'B']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[13, 30, 70], [-1160, 'W']], [[13, 163, 5], [1565, 'B']]], [[[9, 72, 5], [625, 'B']], [[9, 4, 0], [-730, 'W']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 56, 75], [-645, 'W']], [[13, 167, 0], [1650, 'B']]], [[[9, 53, 75], [175, 'B']], [[13, 163, 5], [1565, 'B']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[13, 27, 75], [-1225, 'W']], [[13, 107, 65], [385, 'B']]], [[[9, 12, 65], [-635, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[19, 303, 75], [2375, 'B']], [[19, 77, 5], [-2075, 'W']]]]
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	`[-3415, 'W']`	`[-615, 'W']`	Failed
black count case 1	`[-2175, 'W']`	`[625, 'B']`	Failed
black count case 2	`[-2625, 'W']`	`[175, 'B']`	Failed
black count case 3	`[-2130, 'W']`	`[670, 'B']`	Failed
black count case 4	`[-2330, 'W']`	`[470, 'B']`	Failed
black count case 5	`[-3435, 'W']`	`[-635, 'W']`	Failed
black count case 6	`[-3145, 'W']`	`[-345, 'W']`	Failed
black count case 7	`[-3490, 'W']`	`[-690, 'W']`	Failed

SHA-256 / 61f667ae698af9a5fc075f9f5d9e6611e41c630fd8d23d505ea68e19278d7110

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 - 1) * (size - 1)
    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, 13, 65], [-615, 'W']], [[9, 72, 5], [625, 'B']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[9, 27, 75], [-345, 'W']], [[9, 6, 0], [-690, 'W']]], [[[9, 80, 70], [720, 'B']], [[9, 64, 0], [470, 'B']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[13, 30, 70], [-1160, 'W']], [[13, 163, 5], [1565, 'B']]], [[[9, 72, 5], [625, 'B']], [[9, 4, 0], [-730, 'W']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 56, 75], [-645, 'W']], [[13, 167, 0], [1650, 'B']]], [[[9, 53, 75], [175, 'B']], [[13, 163, 5], [1565, 'B']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[13, 27, 75], [-1225, 'W']], [[13, 107, 65], [385, 'B']]], [[[9, 12, 65], [-635, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[19, 303, 75], [2375, 'B']], [[19, 77, 5], [-2075, 'W']]]]
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	`[-445, 'W']`	`[-615, 'W']`	Failed
black count case 1	`[795, 'B']`	`[625, 'B']`	Failed
black count case 2	`[345, 'B']`	`[175, 'B']`	Failed
black count case 3	`[840, 'B']`	`[670, 'B']`	Failed
black count case 4	`[640, 'B']`	`[470, 'B']`	Failed
black count case 5	`[-465, 'W']`	`[-635, 'W']`	Failed
black count case 6	`[-175, 'W']`	`[-345, 'W']`	Failed
black count case 7	`[-520, 'W']`	`[-690, 'W']`	Failed

SHA-256 / ab7fe76d9f2540e47a5c16c19b269daf88f7340e6933c4d74cda81530a4003f3

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, 13, 65], [-615, 'W']], [[9, 72, 5], [625, 'B']], [[9, 53, 75], [175, 'B']], [[9, 74, 0], [670, 'B']], [[9, 64, 0], [470, 'B']], [[9, 12, 65], [-635, 'W']], [[9, 27, 75], [-345, 'W']], [[9, 6, 0], [-690, 'W']]], [[[9, 80, 70], [720, 'B']], [[9, 64, 0], [470, 'B']], [[9, 4, 0], [-730, 'W']], [[9, 69, 65], [505, 'B']], [[9, 35, 70], [-180, 'W']], [[9, 21, 75], [-465, 'W']], [[13, 30, 70], [-1160, 'W']], [[13, 163, 5], [1565, 'B']]], [[[9, 72, 5], [625, 'B']], [[9, 4, 0], [-730, 'W']], [[13, 111, 5], [525, 'B']], [[13, 13, 5], [-1435, 'W']], [[13, 7, 70], [-1620, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 56, 75], [-645, 'W']], [[13, 167, 0], [1650, 'B']]], [[[9, 53, 75], [175, 'B']], [[13, 163, 5], [1565, 'B']], [[13, 130, 5], [905, 'B']], [[13, 39, 65], [-975, 'W']], [[13, 76, 65], [-235, 'W']], [[13, 132, 65], [885, 'B']], [[13, 27, 75], [-1225, 'W']], [[13, 107, 65], [385, 'B']]], [[[9, 12, 65], [-635, 'W']], [[13, 46, 75], [-845, 'W']], [[13, 137, 0], [1050, 'B']], [[13, 9, 65], [-1575, 'W']], [[13, 114, 65], [525, 'B']], [[19, 309, 0], [2570, 'B']], [[19, 303, 75], [2375, 'B']], [[19, 77, 5], [-2075, 'W']]]]
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	`[-615, 'W']`	`[-615, 'W']`	Passed
black count case 1	`[625, 'B']`	`[625, 'B']`	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	`[-345, 'W']`	`[-345, 'W']`	Passed
black count case 7	`[-690, 'W']`	`[-690, 'W']`	Passed

SHA-256 / 5a06f9022103eab7d7f235a8de4a34840cb4c6e1f104f98a55708b29a70983fe

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 2026-09-29T14:50:19.070690+00:00.

Case digest / 371b692dffa38729f088b79989603e63a643341c6104f48b1fb895c55f4bf38f