Kōichi Ōizumi
1943
Amerika "anzen" handobukku- Hasekura Rokuemon Tsunenaga
- Hasekura Rokuemon Tsunenaga "Keichō Kenʼō shisetsu" kenkyū shiryō shūsei
- Hasekura Tsunenaga
- Hasekura Tsunenaga Keichō kenʾō shisetsu no shinsō
- Honkon no Chūgoku henkan to takokuseki kigyō
- Kaigai rakuraku anzen hadobukku
- Keichō kenʾō shisetsu no kenkyū
- Kirishitan shōgun Date Masamune
- Kokusai gōben kigyō
- Mekishiko ni okeru Nihonjin ijū senshi no kenkyū
- Netsuzōsareta Keichō kenʼō shisetsuki