Hanbun no Tsuki ga Noboru Sora (半分の月がのぼる空, lit. "Sky with a Rising Half-Moon"?), subtitled looking up at the half-moon and also known as Hantsuki, is a Japanese romance light novel series written by Tsumugu Hashimoto and illustrated by Keiji Yamamoto centering on two hospitalized seventeen year olds and the love they begin to share. The series was originally serialized in MediaWorks' now-defunct light novel magazine Dengeki hp and spanned eight volumes released between October 2003 and August 2006.
An anime was adapted from the novels and aired in Japan on the WOWOW television network between January 12 and February 23, 2006 with six episodes. A manga series by B.Tarō was serialized in MediaWorks' shōnen manga magazine Dengeki Comic Gao! between August 2005 and November 2006; two volumes were released. A set of five drama CDs were produced between October 2006 and August 2007 by Wayuta. A live action drama of the series was aired on TV Tokyo between October and December 2006, and a live action film premiered in Japanese theaters in April 2010.
After contracting hepatitis A, Ezaki Yuuichi has been confined to a hospital away from his friends and family, much to his displeasure. To relieve his boredom, he has taken to sneaking out of the hospital, usually putting himself on the receiving end of a beating from his nurse. Upon meeting a girl his age also staying in the hospital, he is immediately captivated by her beauty. Akiba Rika's personality is not quite as captivating as her beauty however. In fact, she is rather selfish, moody, and bossy. But as the two spend more time with each other, they become closer, sharing the ordinary joys and trials of a budding teenage romance, even when darkened with impending tragedy - for Rika's condition does not leave her much longer to live.