Masamichi Taniuchi

Team Ocean Navi after successfully crossing the 40 km Sado Channel in northern Japan

Sado Channel Relays

On 13 June 2018, Kumiko Koizumi, Masamichi Taniuchi, Tamotsu Yoshida, Noriko Kawasaki, Minori Tanaka, Takaomi Modegi, Yukie Makino, Terumi Nakayama and Satoko Murata completed a 43 km crossing of Sado Channel from Sado Island to Niigata Prefecture on the Japanese mainland in 13 hours 7 minutes 4 seconds.
Team Ocean Navi including wetsuited swimmers Taku Wakabayashi, Eri Obiya, Saki Watanabe, Hiroto Kagami, Takeomi Modagi, Masamichi Taniuchi, Kumiko Koizumi, Aya Kurano, Yasuko Takeda, Mayumi Doi, Tanomi Muraki and Nishina Yuichi completed a 12 hour 24 minute 40 km crossing of the Sado Channel from Sado Island to the Honshu mainland on 12 June 2019 observed by Masayuki Moriya with the support of Honma Motoko.
On 28 May 2025, Team Ocean Navi completed a 12 hour 11 minutes 58 second 40 km relay across the Sado Channel in northwestern Japan. The team started at Akadomari Port on Sado Island 35 minutes after midnight. They finished at Teradomari Port on the mainland of Honshu in Nagaoka City at 12:46 pm. The members included Sakae Kataoka, Kimiyo Hokone, Masamichi Taniuchi, Kumiko Koizumi, Utako Hiramatsu, Noriko Kawasaki, Kayo Arihara, Hiroyuki Kobayashi, Satoko Murata, Toshimi Ikegame, Hiroyuki Sugie, and Yuki Arai with observer Motoko Homma, and expedition leader Masayuki Moriya.

Ocean Navi team of Kumiko Koizumi, Masamichi Taniuchi, Tamotsu Yoshida, Noriko Kawasaki, Minori Tanaka, Takaomi Modegi, Yukie Makino, Terumi Nakayama and Satoko Murata completed a relay crossing of the Sado Channel from Sado Island to the Japanese mainland of Honshu in 13 hours 7 minutes 4 seconds on 13 June 2018.