Nintendo Research & Development 1
From the Super Mario Wiki
Nintendo Research & Development 1 (often abbreviated as Nintendo R&D1) was Nintendo's first internal development team. Its founding actually predates Nintendo's entry in the video game market, it being created to focus on the manufacturing of toy guns and other products. It was managed by Gunpei Yokoi for most of its existence. In addition to developing games, R&D 1 designed hardware, including the Game & Watch, the Game Boy and the Virtual Boy.
In 2004, all of the R&D departments were dissolved due to a corporate restructuring. Most of the staff were folded into Nintendo EAD or the newly-created Nintendo Software Planning & Development Group #1.
Mario games developed by Nintendo R&D 1