Hirokazu Yasuhara (安原 広和, Yasuhara Hirokazu; born October 12, 1965), also known as Carol Yas, is a Japanese video game designer. He is most famous for creating the gameplay and levels of the first Sonic the Hedgehog video games for Sega Genesis in the 1990s. These games were based on early game tests and tools developed by Yuji Naka. Yasuhara worked for Sega until 1999. From 2002 to 2008, he worked for Naughty Dog, where he helped design games in the Jak and Daxter series and Uncharted: Drake's Fortune. During this time, he worked with Mark Cerny, who had previously worked at Sega. From 2008 to 2012, Yasuhara was the senior design director at Namco Bandai Games America. In April 2012, he joined Nintendo and worked at the Nintendo Software Technology division. He left Nintendo in 2016 and has since worked for Unity Technologies.
