Naval Institute
This group (kaigun kyoukai) seems to have be an adjunct of the Navy.
It published a lot of naval books and pamphlets.

There is a large variety of Navy Institute badges, most of which seem to
be membership badges. I suppose it is safe to say that the larger and
more ornate the design is, the higher the rank of membership.

Some of the lowest ranks have paint instead of enamel. I will try and
find out more about these.
Gold plated member badge
Silver plated member badge with box
Navy Institute enameled (not painted) member badge.
Gold gilt.
This is similar to a member badge, but the enamel rays are orange. And the
inscription reveals this to be a badge commemorating the successful passing of a
course of studies. Inscribed 'Naval Institute, Military Lectures Completion Badge.'
A beautiful enameled Merit badge from the Naval Institute. Marked 'Merit Badge, Naval Institute.'
A painted Merit badge from the Naval Institute. Marked 'Merit Badge, Naval Institute.' This is probably
aluminum and circa late in the war. It is marked the same as the nicer badge above, but the quality is
much lower.
Large medallion from the Naval Institute.
Inscribed ' Showa 11 [1936] April, Naval
Institute Fukuoka Prefecture Branch Meeting

The word I translated as 'meeting' can also
mean 'tournament.'

The rim has some dents.
Inpaku Navy Institute Life Member Badge. This group may have no relation to
the Naval Institute...
Small cheaply made Naval Institute badge
Naval Institute enamel merit badge.
Naval Institute Special Member Badge.
Inpaku Navy Institute Discussion Association Member
Badge. With original ID card, dated Meiji 42 [1909] July 13.
Stamp on box bottom
Regular Member wood doorplate with
original envelope dated Showa 19 [1944].
Regular Member Badge award document dated Showa 19 [1944].