Search gender: all male female Kosan Boy Name Meaning, Kanji Variations. 1 names found. gender: all male female Name: kosan Katakana: コウサン 0 Kanji: 甲三 Meaning: 甲Carapace 三Three. The third. Kanji to represent the number 3 (three).Again. Again and again. Many times. You can save your favorite names with NAZUKE PON > About Japanese Names > Search For Japanese Names > Kosan Boy Name Meaning, Kanji Variations.