In the Empire of Japan, Navy Commemoration Day /海軍記念日, Kaigun Kinen'bi/ was celebrated on May 27. It was established in 1905 to commemorate the Battle of Tsushima and was abolished in 1945 after Japan's defeat in the WW2.
Navy commemoration day posters.
輝く海軍記念日 - Shining Navy Day
無條約第一年 海軍記念日 - First Navy Commemoration Day with No Treaty Obligation /1936/
海軍省 - Ministry of the Navy
輝く紀元二千六百年 - Shining 2600th Year of Imperial Era /1940/
海軍記念日 - Navy Commemoration Day
Navy Day celebration in 1944.
Ministry of the Navy Badge.
Quite often the original paper wrappings for these badges became lost and badges become unidentifiable.
記念 - Commemorative
海軍省 - Ministry of the Navy
One of the main manufacturers of these badges was the Ikoma workshop in Osaka https://asiamedals.info/threads/badges-marks-and-history-of-ikoma-workshop.20961
大阪 生駒時計店謹製 - Made by Ikoma Watch Shop, Osaka