Nintendo Research and Development 1 (also known as R&D1) is 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, one of the creators of the Metroid series. In 1986, several developers left R&D1 to form Intelligent Systems, which became another first party developer for Nintendo. 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 Wario.