天の声バンク (Ten no Koe Bank) is not a video game. It is not a manga. It is not a hybrid of the two. It is not a Big Mac and chips. 天の声バンク (Ten no Koe Bank) is an accessory that was released for the NEC PC Engine video game console in 1991. The PC Engine console was not afforded a great deal of on-board memory, and managing save games was a problem that quickly required addressing.
If you have ever owned the wonderful Psygnosis video game Microcosm, specifically on the SEGA Mega CD, you may have come across a small paper pamphlet written entirely in Japanese. If you can’t read Japanese, or if your copy of Microcosm didn’t come with this fun little informational pamphlet and you appreciate a healthy dose of text spat out by an online translation engine, then your luck is well and truly in!