Physically very similar to Okinoshima in size, appearance and layout, its main armament was changed to four 127 mm Type 89 dual purpose guns, intended to give Tsugaru better AA capabilities than its predecessor.

Following the success of this mission, in January 1942, Tsugaru deployed from Jaluit together with Okinoshima, under the overall command of Admiral Sadamichi Kajioka to participate in “Operation R” (the invasion of Rabaul and Kavieng).

[4] On 31 May, Tsugaru was assigned to “Operation KON” (the Relief of Biak), transporting reinforcements from Zamboanga on Mindanao in an effort to counter the American landings.

On 21 June, after departing Sorong, New Guinea for Halmahera Island, Tsugaru was torpedoed by the Royal Dutch Navy submarine K-XIV, which caused severe damage.

After temporary repairs, she attempted to reach Manila, but was sighted on 29 June near Biak by USS Darter (SS-227), which fired a full spread of six torpedoes.