Kaai Yuki (歌愛ユキ) is a Japanese VOCALOID developed and distributed by AH-Software Co. Ltd., and was initially released in December 2009 for the VOCALOID2 engine. Yuki’s vocals are based on an elementary school student. With her voice provider being a young girl the identity of her provider has never been revealed for legal reasons. She was the first female VOCALOID whose voice samples are not produced from an adult. There is currently ongoing development for an upgrade to the VOCALOID4 engine, using a new voice provider for the growl components. This was due to the fact her provider had matured, making re-sampling problematic. On September 30th, Yuki was confirmed to only receive a Natural voicebank, which could be purchased on its own or in a starter package. Her release date was announced to be October 29th, 2015.