Yuukisan (有機酸, also spelled as Yukisan, styled as uki3), and also known as ewe, is a VOCALOID producer.

His works, bearing somewhat stoic elements yet combined with a unique view of the world and quality sound creation, are highly appreciated by listeners.

Hatsune Miku is primarily utilized in his works, though on several occasions, he has also used flower. Instances of his most notable songs include quiet room, krank, and lili.. Apart from composing songs, he is also known for making self-covers; some of which have exceeded the VOCALOID versions.

In November 2018, he announced the change of his name to “Yoh Kamiyama” (神山羊) as an artist, whereas his alias as a VOCALOID producer would be kept as Yuukisan.