Hikaru Kaihatsu (開発 光 Kaihatsu Hikaru), known in YouTube as Hikakin (typeset as HIKAKIN) is a Japanese YouTube celebrity. His video of his Super Mario Bros. beatbox went viral in 2010, reaching over 3.8 million views by mid-September of that year. He, alongside fellow Japanese YouTuber Megwin, quit their day jobs in 2012 to focus entirely on their channels. He also collaborated with Gille, appearing in her promotions for her single "Try Again" where it is stated that he is one of the most popular Japanese YouTubers. In December 2012, Hikakin released his first album, a collaboration with video game music composer Hideki Sakamoto, for the soundtrack of the Echannel drawing application of the PlayStation Vita.
In May 2013, Hikakin participated in the Social Star Awards and the subsequent Singapore Social concerts, performing with Aerosmith during their stage set and beatboxing before performing with the band on "Walk This Way".
In October 2014, Hikakin was one of the performers for the first YouTube FanFest in Tokyo, Japan. At the same YouTube FanFest, Japanese breakbeat music duo Hifana performed with their instruments and using Hikakin's beatbox broken down into several parts, they were able to create a total new combination of his Beatbox and with their instruments.
In December 2014, Hikakin went to New York City to do another collaboration video with singer Ariana Grande, doing a beatbox of that song, while she was singing Break Free. On the same month, Hikakin uploaded a beatbox video which featured famous American singer Ne-Yo in it. They performed Ne-Yo's new song, Coming with You and his famous song from 2007, Because of You.