Hirokazu Yasuhara (also credited as Carol Yas) (born October 12, 1965) is a Japanese video game designer. He designed the gameplay and stages of the majority of the initial Sonic the Hedgehog video games for Sega Mega Drive based on technical demos and engines coded under the lead of Yuji Naka and characters designed by Naoto Oshima. In spite of Yasuhara and Oshima's key creative roles, programmer and producer Naka has since become identified as the creator of Sonic the Hedgehog by the mainstream gaming press. Yasuhara stayed with the franchise until 1994 though he worked on Sonic 3D Blast in 1995, Sonic Xtreme in 1996 and Sonic R in 1997. He then joined Naughty Dog, working on the Jak and Daxter series and , collaborating again with former Sega employee Mark Cerny. He was the senior design director at Namco Bandai Games America. In April 2012, Yasuhara joined Nintendo where he accepted a position at Nintendo Software Technology.