There are three ‘T’ Casios I know of – but what their purpose is, is a mystery, at least to me.
The three-game MG-777, BB-9 baseball, and the BG-15 boxing calculator all come with a rare T version. Strange thing is, the games are all identical to their non-T versions, the only difference being the graphics on the case – and in the case of the MG-777T there isn’t even this anomaly.
Game calculators are scarce enough anyway, and with the Casio company’s lack of documentation or assistance concerning their vintage models, you can only speculate on the need for the ‘T’. I’ve heard it mentioned that T = Tournament, but if this were the case, you’d expect some multi-player scoring or other functionality to be built into the games. I guess if there were officially sanctioned competitions in Japan at the time the calculators were released to boost marketing the Tournament story could be plausible but it would take someone who was there at the time to confirm it, so until then it’s all guesswork.
The one thing the T versions have in common is that the revised graphics make more of the game itself. Compare the BG-15T with the standard BG-15 below.
For starters the colours of the BG-15T are more vibrant, that red is almost pink and the blue is much lighter (close to highlighter blue). The name BOXING is larger on the BG-15T, the boxer around the game key is larger and the instructions for playing the game at the bottom are much more engaging (particularly Punch)!
So if nothing else, the T model could just be a re-release due to the calculator’s popularity and Casio, knowing they were onto a good thing with the calculator plus game concept opted to make more of the game function to appeal to a younger audience. But like I say, it’s all just speculation.
There’s no added benefit to playing the T version, other than knowing you’re playing a rarer game so don’t get too punchy on the keys. On the whole boxing was a great seller for Casio perhaps evidenced by the number of versions they produced – the BG-15 and BG-15T were joined by the BG-8 (small ‘ladies’ version) and BG-20 (large screen version).
The two BG-15Ts I’ve owned both came from Australia so another thought might be it was a down-under version of the calculator – which wouldn’t be the first time the Southern Hemisphere got a different version than the rest of the world. Nintendo’s rare widescreen Game & Watch Egg EG-26 is a direct clone of Mickey Mouse MM-25 but for some reasons (licensing probably) was only released in non-Asian/American/European markets.