You can read about the Army Type 98 on Ohmura's site - Army Commissioned Officer Gunto - Type 98
Care and cleaning - Guide to Care for Japanese Sword - Japaneseswordindex.com
There were several smiths that signed under that name in WWII. I don't know how to tell which one was yours:
"KANEMASA (兼正), Shōwa (昭和, 1926-1989), Gifu – “Nōshū-jū Kanemasa” (濃州住兼正), “Shuryūshi Kanemasa” (炷龍子兼正), “Nōshū Seki-jūnin Kanemasa” (濃州関住人兼正), real name Ōno Masami (大野正巳), he is also listed with the first name Masaki (正己), born in February 11th 1923, he was adopted by the Ōno family and studied under Morita Kaneshige (森田兼重), gō Shuryūshi (炷龍子), younger brother of Yoshida Masaaki (吉田正明) (see picture right)
KANEMASA (兼正), Shōwa (昭和, 1926-1989), Gifu – “Kanemasa” (兼正), real name Kuriki Shōichi (栗木正一), he is also listed with the family name Kurimoto (栗本), born Februar 15th 1918, he studied under Kojima Kanemichi (小島兼道) and worked as a rikugun-jumei-tōshō, ryōkō no jōi (Akihide), Fifth Seat at the 6th Shinsaku Nihontō Denrankai (新作日本刀展覧会, 1941)
KANEMASA (兼正), Shōwa (昭和, 1926-1989), Gifu – “Kanemasa” (兼正), real name Toki Yoshihira (土岐善平), born November 21st 1897, he worked as a guntō smith and died November 2nd 1980
KANEMASA (兼正), Shōwa (昭和, 1926-1989), Gifu – “Kanemasa” (兼正), real name Masunouchi Kenzaburō (升内兼三郎), he worked as a guntō smith
KANEMASA (兼正), Shōwa (昭和, 1926-1989), Aichi – “Bishū-jū Takeuchi Kanemasa kore o saku” (尾州住竹内兼正作之), “Bishū Kōzōji-jū Takeuchi Kanemasa” (尾州高蔵寺住竹内兼正), real name Takeuchi Kanesaburō (竹内兼三郎, the first name can also read Kenzaburō), rikugun-jumei-tōshō, he was no longer working as a swordsmith after World War II, Fifth Seat at the 6th Shinsaku Nihontō Denrankai (新作日本刀展覧会, 1941)
KANEMASA (兼正), Shōwa (昭和, 1926-1989), Tōkyō – “Shōjū Kanemasa” (小銃兼正), “Kanemasa” (兼正), real name Murata Tsuneyoshi (村田経芳), he worked for the Akabane Arsenal (赤羽造兵廠)"