Home / Proof Marks / Japanese — Miroku two-letter date code

Japanese — Miroku two-letter date code

Export, import and country-of-origin stamps · Modern Japanese production.
What it looks like
Two letters at the end of the serial number.
Where it is on the gun
Barrel or receiver, as part of the serial number.
Date range
Modern Japanese production.

What it tells you

What this mark authorises you to say

The year of manufacture, in the simplest system of any gunmaking nation: Japan has no gun-barrel proof house, so Miroku, which has made the traditionally styled Brownings, adopted Browning’s own date-coding system and put two letters at the end of the serial number. On a Japanese-made over-and-under or a Browning with a Japanese barrel, this is the most direct dating evidence available.

What it does not tell you

What this mark does NOT say

It is a maker’s code, not a proof mark — Japan does not proof gun barrels, so any "proof mark" claimed on a Japanese gun is either a British or Belgian mark applied on import, or not a proof mark at all. The system has also changed over the decades, so the two letters must be read against the table for the right period.

Where the sources are uncertain

Miroku’s own coding has changed more than once, and the tables in circulation cover different spans of years. Owners of recent guns report the last two letters no longer behaving as the older tables predict.

Sources for this page

Every claim above is attributed. The class of source is shown with each one, because a national proof house and an anonymous forum table are not the same evidence — and on proof marks the difference matters.

Related on this site

Makers whose guns carry marks like this:

Reading marks to identify and date a gun

Proof marks name the test and the era. The serial number, where a maker published a browsable chart, can name the year. The lookup cites the threshold behind every result.

Open the serial number lookup

Other export, import and country-of-origin stamps

Mark descriptions observed and verified 2026-10-14. Proof marks are stamped by hand on guns up to a century old; a photographed stamp and a description in a book are not the same evidence. If a mark on your gun does not match anything here, that is a real answer — see the notes on unidentified marks.