Japan Post 4-State

Overview

The Japan Post Customer Barcode (Japanese Post 4-State Customer Code, JP4SCC; sometimes called the "Kasutama" barcode) is a height-modulated, four-state barcode used by Japan Post for automated mail sorting [1, 2]. Like the other members of the four-state family it descends from Royal Mail's rm4scc, encoding data through bar height/position rather than width [2]. It encodes a 7-digit postal code plus up to 13 characters of address-indicator data, supporting digits, uppercase letters and hyphens [1, 2].

History

Japan Post's customer barcode follows the four-state, height-modulated pattern pioneered by Royal Mail's rm4scc and adopted by several national posts for automated address sorting [2]. (A precise public adoption date was not established from the sources consulted.)

Technical specification

Four-state bar structure. Each character is built from bars in four states, conventionally valued [1]:

• Long bar (full height) — value 1.
• Semi-long bar, upward (ascender) — value 2.
• Semi-long bar, downward (descender) — value 3.
• Timing bar (tracker) — value 4.

Symbol layout [1, 2]:

1. Start bars — values 1, 3.
2. Postal code — 7 characters (21 bars); a hyphen in the printed code (e.g. 108-0075) is for display only and is not encoded.
3. Address indication number — up to 13 characters (39 bars), padded with filler characters if shorter.
4. Check digit — 3 bars, immediately before the stop bars.
5. Stop bars — values 3, 1.

Character set and control codes. The symbology represents digits 0–9, uppercase A–Z and hyphen. Because each letter cannot be a single base symbol, letters are encoded with control characters: CC1 prefixes letters A–J, CC2 prefixes K–T, and CC3 prefixes U–Z. Additional control codes (e.g. CC4 for normal priority and CC7 for highest priority, plus fillers) round out the set [1].

Check digit. A check character occupies the 3 bars before the stop bars and is used to validate the symbol [1, 2].

Placement. The barcode must sit no less than 10 mm from the top or side edges and 15 mm from the bottom edge of the mail piece, with inclination held within about 5 degrees [1, 2].

Use cases

• Automated sorting of Japanese mail by postal code and address indicator [2].
• Encoding a 7-digit postal code (introduced in the Japanese postal system) plus an address-detail string so sorting machines can route to a finer destination [1, 2].

Implementations

• OkapiBarcode — Java, ~394 stars, active 2025; supports Japan Post among its postal symbologies [3-okapi].
• productdevbook/etiket — TypeScript, ~409 stars, active 2026; zero-dependency four-state engine covering Japan Post, RM4SCC, KIX and Australia Post [3-etiket].

Comparison

The Japan Post code is a four-state descendant of rm4scc [2], but it makes two distinctive design choices. First, it uses an explicit control-character scheme (CC1/CC2/CC3 …) to shift between letter ranges and to flag priority, rather than encoding each letter as its own self-contained character as RM4SCC does [1]. Second, its bar-state numbering and start/stop values (start 1,3, stop 3,1) differ from those of RM4SCC and the australia-post-4-state code [1]. It is simpler than the Australia Post and mailmark variants in that it relies on a short check digit rather than full Reed–Solomon error correction, while still retaining a checksum — unlike the Dutch kix, which drops start/stop bars and the checksum altogether.

Fun facts

• Letters are not encoded directly: an A–Z character is represented by a control code plus a digit, so a single visible letter consumes more than one barcode character [1].
• The symbology carries the nickname "Kasutama" barcode in some references — a transliteration of the Japanese word for "customer" [2].

Status

In use. The Japan Post Customer Barcode remains a documented and supported four-state postal symbology for Japanese mail automation, with implementation parameters published by multiple barcode SDK vendors [1, 2].

Sources

1 Japanese Post 4-State Customer Code — Barcode Guide — Seagull Scientific 2 Japan Post 4-state Barcode — Neodynamic 3 OkapiBarcode — GitHub (woo-j) 4 Postal Barcodes overview — Compart 5 Japan Post 4-State Customer Code — overview — Online Tool Center

Deployments

No country reports mention this standard by name.