Seiji Nakamitsu also uses the pseudonym "Makoto Sugimoto."

References:

• Gay pink film distributor ENK Promotion: "Sugimoto Makoto (now known as Nakamitsu Seiji)" (Source)
• "Actually, Seiji Nakamitsu and Makoto Sugimoto are the same person" (https://blog.goo.ne.jp/seyfriheard/e/9f993e9de034f6aef5d9df78aa13e19b)
• "Nakamitsu's stage name has changed from Nakamitsu Seiji to Sugimoto Makoto to Nakamitsu Seiji... [...] He said that at one time, the fact that the same male actor was appearing in many pink films was considered a problem" (http://blog.livedoor.jp/hidesmile/archives/1485884.html)
• http://jhmd.jp/media/index.php?title=%E3%81%AA%E3%81%8B%E3%81%BF%E3%81%A4%E3%81%9B%E3%81%84%E3%81%98

Photo comparison:

• Look at this picture of "Makoto Sugimoto": https://mydramalist.com/people/140907-sugimoto-makoto
• Now look at this picture of "Seiji Nakamitsu": https://www.themoviedb.org/person/1111190-seiji-nakamitsu