Not only should you look at Kubota-san's page, but I also heartily recommend the Pyuuta Palace. Both are in Japanese.
Updates and corrections are naturally welcome. Last modify 26 Jan 2009.
The history and major models of the Pyuuta series.
All Pyuuta-series cartridges, tapes and peripherals are listed with the American versions and releases on the main catalogue page.
These are all of units I personally own; yes, I really do have at least one of each model. Subparts:
Photographic series of the original Tomy Pyuuta, the ancestor of the Tutor line, as well as scans taken from the manual of the original system. I've also disassembled the unit to demonstrate the firmware and innards, and taken screenshots of major functions to demonstrate the operating system.
Shortly after the Pyuuta's rollout came the Junior, an adorable little console with a surprisingly robust interface. I've scanned portions of the manual and cracked open the case to show the innards, and included an in-depth screengrab series to show off its primitive but unbelievably friendly operating system software.
An easy hack to get composite signals out of your Jr. to connect it to American monitors. Should also work for the Mk II. Soldering required; you do this modification at your own risk.
The elusive "Mark 2" was Tomy's final attempt to rekindle the Pyuuta line, this time with American blood. Although I don't have the manual (yet), I've also disassembled the machine to demonstrate *its* firmware and some of its unusual similarities (and differences) to the prototypical American version.