Nintendo Research and Development 1 (任天堂開発第一部) (R&D1) was Nintendo's oldest development team. Its creation coincided with Nintendo's entry into the video games industry, and the original R&D1 was headed by Gunpei Yokoi. The developer has created several notable Nintendo series such as Metroid, Zelda, Tetris, Mario Bros., and Donkey Kong.
R&D1 developed the hugely successful Game Boy line, which was released in 1989. They developed some of the line's most popular games, such as Super Mario Land, and created the character of Wario.
In 2005, Satoru Iwata restructured the Nintendo R&D1 team. Many of the staff members were later reassigned to the Nintendo SPD team, which in turn merged with Nintendo EAD in 2015 to form Nintendo Entertainment Planning & Development. More: en.wikipedia.org.