Japanese Spreadsheet-Error Incident Corpus (Anonymized, Translated)

N = 65 cases. Compiled from openly available news reports and disclosed documents; this is a convenience sample, not an exhaustive census, so apparent time/regional patterns reflect search coverage rather than true incidence rates. Organization, school, and place names have been removed or generalized to a broad region/entity type; source URLs have been removed. Cases were identified through Google web searches conducted from Japan on July 11, 2026, using the query pattern "表計算 ミス (prefecture name)," repeated across each of Japan's 47 prefectures. As such, this corpus should be understood as a convenience sample bounded by search-engine indexing and query design, not a systematic or exhaustive survey. Source URLs for all cases are available upon reasonable request, with one exception: the entrance-examination case (Case 12) involves a minor examinee, and its source is withheld from the supplementary material to avoid enabling re-identification. Its content was verified through the same search process described above.