Wares Blade is a Japanese RPG made in 1988 and is still going strong and has a strong following in Japan.
The game is set in the world of Ahan which is a typical fantasy world but the difference is that the world uses giant steampunk mechs and cyberware and mixes them with magic.
The system used for this game is an adaption of the Chaosium Call of Cthulhu percentile system but in 2008 Waresblade was adapted to the D20 system.
Mech combat is handled a modified battletech /wargame style but this has been changed in recent editions.
This particular RPG entry deals with the earlier d10 version of the system.