The Japanese Postal CSV Is a Nightmare, and This Developer Parsed It
Parsing the Infamous Japanese Postal CSV
Japan Post's postal code CSV, ken_all.csv, is notorious for its bizarre formatting: lines split mid-neighborhood, unquoted fields with a different comma, and parenthetical notes meant for humans. Developer polm released posuto, a Python library that parses this data into a usable format, and shares the quirks he encountered, including the 66-line entry for a single postal code and the low-quality romaji file.
I used to process CSV and other files from hundreds of different providers at an old job and I saw many horrors, but I've never seen this particular formatting choice anywhere else.