Here's what Sesko has on him:
"TOSHIHIDE (俊秀), Shōwa (昭和, 1926-1989), Hokkaidō – “Ōmi no Kuni Shiga Tarō Minamoto Hideaki” (近江国志賀太郎源秀明), “Minamoto Toshihide” (源俊秀), “Zuisen Horii Toshihide” (瑞泉堀井俊秀), real name Horii Kaneyoshi (堀井兼吉), he was born on the second day of the third month Meiji 19 (明治, 1886) in the village of Shimosaka (下坂) in Shiga Prefecture, 1905 he entered an apprenticeship under Horii Taneaki (堀井胤明), he signed in early years with Hideaki (秀明), a name that was granted to him in 1913 by the NBTHK, 1911 he married the daughter of Taneaki and was adopted into the Horii family, thereupon he changed his name to Shiga Tarō (志賀太郎), the name change of the smith name to Toshihide took place in December 1933 with the birth of emperor Akihito (明仁) because he refrained out of respect from using the same character of “Aki” (明), he died in 1943, shinpin no retsu (Akihide), Special Honor Seat at the 6th Shinsaku Nihontō Denrankai (新作日本刀展覧会, 1941)"
Your blade is dated June 1929, so pretty early for a WWII smith.
The sword is a Type 97 Japanese Naval officer's sword. You can read about them on Ohmura's site here: Naval Commissioned Officers Sword - Ohmura
The tsuba (handguard) is civilian, so unusual to see on a Navy kaigunto. Maybe it was something the officer brought from home.