Salio
From Sega Retro
Salio Inc. (サリオ株式会社) was the only third-party company to publish games for the Mark III/Master System in Japan. Prior to the Mega Drive, very few third-party companies supported Sega's platforms due to their lack of a licensing model. Before Salio, the only third-party company to publish games for Sega platforms, Tsukuda Original, produced game cartridges for the SG-1000/SC-3000 platforms (including their own clone hardware, the Othello Multivision), but they abandoned this business prior to the launch of the Mark III.
Salio was actually a dummy company created by Tecmo so they could circumvent Nintendo's exclusivity policy on third-party publishers and release games on competing platforms without repercussion. Salio's mailing address was actually the location of Tecmo's original headquarters (back when they were known as Tehkan Ltd.), which was located in the Azumabashi district of Sumida, Tokyo (the actual Tecmo had already moved to Chiyoda in 1985). Only two game cartridges were published by Salio for the Mark III, with both games being released under the "Silver Cartridge" branding, in contrast to the "Gold Cartridge" branding used by Sega for their first-party cartridges. Tecmo wold publish games for later Sega platforms under their own name.