Hōkoku Maru was designed as a cargo liner for Shosen Line's scheduled services to South America.

However, the Japanese admiralty influenced the design of the Hōkoku Maru-class, to make them suitable for use as troop ships.

Despite her intended role as a commerce raider, little attempt was made to disguise Hōkoku Maru as a merchant ship.

Her guns were fitted with gun-shields and were left in open sight,[3] and she was painted in two-tone naval camouflage.

Hōkoku Maru was commissioned into the Japanese Navy on 20 September 1941 under the command of Captain Aihara Aritaka.

Returning to Singapore, Hōkoku Maru was re-equipped with two Aichi E13A (Allied reporting name "Jake") floatplanes, and an experimental two-tone dazzle camouflage scheme.

Four days later, on 11 November 1942, they encountered the Dutch armed tanker Ondina, escorted by the Royal Indian Navy corvette HMIS Bengal off the Cocos (Keeling) Islands.

As Hōkoku Maru engaged, Bengal and Ondina returned fire, and a shell, probably from Ondina's single 4-inch (102 mm) gun, hit Hōkoku Maru's starboard torpedo mount, causing an explosion and uncontrollable fire which spread to the aft magazine.