The Sega Mark III, the original Japanese version of the Master System, carries over the same expansion port as the SG-1000 line. Because of this, the Mark III is also compatible with the SK-1100 computer keyboard add-on and a few Mark III games can even be controlled from an SK-1100 instead of a regular controller. By the end of 1986, this feature was largely dropped and in some game manuals, Sega even advised SK-1100 owners to disconnect the accessory before playing the game as it does prevent a handful of games from booting.
Note that the SK-1100 will not connect to a Master System due to its different expansion port.
| Game Name | Notes |
|---|---|
| Action Fighter | Not documented in manual, basic controls only |
| Alex Kidd in Miracle World | Not documented in manual, basic controls only; F moves left, V moves right, Pi punches and Ins/Del jumps |
| Ashura | Not documented in manual, basic controls only; 1 moves up, Q moves down, A moves left, Z moves right, Hiragana key shoots, comma fires rockets |
| Astro Warrior | Not documented in manual, basic controls only |
| Black Belt/Hokuto no Ken | Not documented in manual, basic controls only |
| Choplifter | Not released in Japan, basic controls only |
| Comical Machine Gun Joe | Basic controls only |
| F-16 Fighting Falcon | All of the controls are available on the keyboard, meaning that there is no need to connect two controllers. Two Mark III and SK-1100 setups can also be linked together via the printer port for head-to-head play. |
| Fantasy Zone | Basic controls only |
| Ghostbusters | Not released in Japan, basic controls only |
| Ghost House | Basic controls only |
| Global Defense/SDI | Partial support, game has no sound and only the cursor can be moved; 2 moves up, W moves down, S moves left, X moves right and period fires |
| Golvellius/Maou Golvellius | Not documented in manual, basic controls only; 1 moves up, Q moves down, A moves left, Z moves right, Hiragana key swings sword, comma jumps |
| Great Baseball (1985) | Basic controls only |
| Great Soccer (1985) | Basic controls only |
| Hang-On | Basic controls only |
| My Hero/Seishun Scandal | Basic controls only |
| Pit Pot | Basic controls only |
| Pro Wrestling/Gokuaku Doumei Dump Matsumoto | Basic controls only |
| R-Type | Not documented in manual, basic controls only; 1 moves up, Q moves down, A moves left, Z moves right, Hiragana key shoots, comma controls Force |
| Satellite 7 | Basic controls only |
| Space Harrier | Not documented in manual, basic controls only |
| Spy vs. Spy | Basic controls only |
| Super Tennis/Great Tennis | Basic controls only |
| Teddy Boy | Basic controls only |
| Transbot/Astro Flash/Nuclear Creature | Basic controls only |
| World Grand Prix/The Circuit | Basic controls only |
| Zillion II: The Tri Formation | Not documented in manual, basic controls only, game has no sound; 2 moves up, W moves down, S moves left, X moves right, period fires |