It is possible that this tag was misappropriated from the PlayStation version. The PS1 port of SRW F had a serial number SLPS-02100 to SLPS-02105 for the two discs. "21M" could be a truncated reference to the PSX release (SLPS-021M?), though for the Saturn, this is technically incorrect.
SRW F features a legendary roster that spans decades of mecha history. Players choose between a (high power/defense) or Real Robot (high mobility/accuracy) protagonist, which changes the starting units and early story path. Super Robot Taisen F -Japan- -Rev B- -21M-
However, like many large-scale Japanese games in the late 90s, the initial pressing (Rev A) had bugs. This leads us to our keyword. It is possible that this tag was misappropriated
Super Robot Taisen F (Japan, Rev B, 21M) – Deep Dive & Thoughts SRW F features a legendary roster that spans
This is a critical qualifier. While Super Robot Taisen F did receive a North American release? Not officially. In fact, SRW titles rarely left Japan until the GBA/PS2 era. The "-Japan-" tag indicates this is a Japanese region release (NTSC-J). For a Saturn game, this means:
Denotes the of the software. This version typically includes minor bug fixes or script corrections that were not present in the initial "Rev A" (1.0) launch. -21M-
In the world of Sega Saturn collecting and disc preservation, these codes are critical for identifying the exact print of a game.