Seapost -> Japanese Seaposts
Japanese Seaposts
By Mike Dovey
Japanese vessels first commenced using Sea Post Office cancellations in 1902 and continued until 1941 when they ceased due to the outbreak of hostilities between the USA and Japan in WWII. Paquebot marks were issued to vessels sailing not only from Yokohama to Seattle, and Japan to San Francisco via Honolulu, but also to vessels sailing from Japan to Europe.

Type 4023 posted from the HEIAN MARU in 1934
Table of listed Japanese paquebot cancel types:
![]() |
![]() |
![]() |
Type 4023 (Studd A211) | Type 4024 (Studd A214) | Type 4025 |
![]() |
![]() |
![]() |
4026 (Studd A212) | 1 (also 3471D) | 2 |
![]() |
![]() |
![]() |
3 | 4 | 5 |
The above cancel types are known posted from the following vessels:
Type | Vessel | Type | Vessel |
---|---|---|---|
4023 | ASAMA MARU | 4024 | AMERICA MARU |
HEIAN MARU | CHIGO MARU | ||
KAGA MARU | TATSUTA MARU | ||
TAITO MARU | TATUTA MARU | ||
TENYO MARU | |||
4025 | none reported yet | 4026 | HIKAWA MARU |
SIBERIA MARU | |||
1 | YAWATA MARU | 2 | HIYE MARU |
3 | YOKOHAMA MARU | 4 | NITTA MARU |
5 | CHICHIBA MARU | ||
KAMAKUBA MARU | |||
TITIBU MARU |

Type 4026 posted from the SIBERIA MARU in 1930
There are certain cancellations used on board vessels that are very similar to paquebot marks used on the mainland in Japan especially at Yokohama (the mark 3471D and 1 above is a prime example). Only by very careful examination can it be ascertained as to whether a cover is mainland or posted on board a vessel.

Type 1 posted from the YAWATA MARU in 1940 (same as 3471D)
References:
Paquebot Cancellations of the World, 4th Edition by Mike Dovey & Keith Morris
Paquebot Cancellations of the World, 3rd Edition by Roger Hosking
Gustav Lund's "The Paquebot Marks of the Americas".
Related Links:
The main Japanese Antarctic Support vessel Shirase carries a sea post office.