Hand-painted Engineer soldier cup from WW1, specifically Siberia.
This is the first soldier cup I have seen from this conflict. The design
shows a Japanese soldier and a large explosion. The characters read
'
9th Engineer, Siberia, Discharge Commemorative.'
The Siberian Expedition (some might say invasion) happened during the years 1918-22.
Although it was initially done as an international operation to rescue some Czech troops, the
Japanese stayed and expanded their territory after the other countries had withdrawn. This
caused international protests in addition to lack of domestic support.

70,000 troops were dispatched, yet cups labeled 'Siberia' are scarce, probably because of its
failure. Much as cups from disastrous conflicts like the Nomonhan Incident and later Pacific
War island battles were rarely (if ever) made, Siberian items were also not popular among
returning troops.
Siberia is now written in the phonetic
Katakana script, but pre-war sources used
the kanji. There are four kanji in Siberia.
Read from right to left.
Cups from the Siberian Expedition have no unifying theme. The patterns vary
and can really be anything, flags, stars, blossoms, etc.

I have seen tokkuri labeled SIberia, but these are quite rare.
Inscribed 'Siberia, Victorious Return Commemorative'.
Inscribed 'Siberia Dispatch, Victorious Return
Commemorative'.
Inscribed 'Siberia
Dispatch,
Victorious Return
Commemorative'.
Inscribed 'Siberia Dispatch Commemorative,
25th Infantry, Sazama'.
Inscribed 'Dispatch to Siberia, Disbandment
Commemorative, 9th Infantry'.
Inscribed 'Siberia Dispatch Commemorative, 7th Infantry, 12th Battalion'.
Inscribed 'Siberia Dispatch, Victorious Return Commemorative'.
A rare masu-shaped (square) sake cup from the Siberian
Expedition.  The central pattern has an Army star and insignia
that might be Cavalry Academy.
See here for another example.
Inscribed on all four sides: 'Dispatch Army, Victorious Return
Commemorative, Siberia, Shinno'.
Inscribed 'Army Vehicle Unit, Siberia Dispatch, Victorious Return
Commemorative, Tezuka.' Rare to find a cup labeled 'Vehicle Unit.'
Siberian Expedition (1918-22)