Some kind of Naval Group. I'm
not sure if the badge on the
cup is a simplified version of
the membership badge, but I
put them together for
comparison.
The cup is from the pre-war Imperial Sea Disaster Rescue Society.
In Japanese:
Teikoku Suinankyuu Saikai. Since this group is still active,
post-war cups can also be found. Perhaps one way to determine if the cup
is pre-WW2 is the inclusion of the phrase 'Teikoku [Imperial]'. This was not
used after 1945. However, even if this phrase is lacking, the cup could be
pre-1945.

Although the symbol of this group is usually a trident and axes, the design
here--and most often found on this group's cups--is a life preserver. The
characters on the cup read 'Imperial Sea Disaster Rescue Society,
Yamagata Division.'
Imperial Sea Disaster Rescue Society
Two others, almost no differences in the patterns.