Sanshiki
Sanshiki is a shell or ammunition model.
Also recorded as Type 3 Shell.
Overview
Japanese anti-aircraft shell.
In detail
It is associated with Empire of Japan.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“San Shiki (anti-aircraft shell)”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q10866016: Sanshiki
Consult the source