THE Japanese have a new “kawaii” obsession — the buttocks of hamsters, captured in photographs — that has led to the publication of two picture books dedicated to the trend.

According to Jun Hongo of the Wall Street Journal, the new trend is called hamuketsu, which comes from the combination of the word hamster and ketsu, Japanese for buttocks.

Both Hamuketsu by Basilico Co and Kawaisa-ni Monzetsu Hamuketsu (Hamuketsu: So Cute You Could Faint) by Sekai Bunka Publishing Inc, recently published picture books, were inspired by the trend.

Basilico Co has so far managed to sell 7,000 copies of Hamuketsu, which featured hamsters’ buttocks in all of its 96 pages, after the book’s March 12 launch.

“The great thing about hamuketsu is that it is delightfully cute. I can’t stop smiling when I see these butts,” spokesman at Basilico Co, Takeshi Takahashi, told the Wall Street Journal.

Sekai Bunka Publishing Inc have sold 30,000 copies of Kawaisa-ni Monzetsu Hamuketsu since its publication on April 19.

Yukako Minami, spokesperson for Sekai Bunka Publishing Inc, said that initially only 7,000 copies of the book was printed, but the book soon ran out of print.

Minami said that male hamsters tend to be more popular with the fans of the craze as the males tend to “have bigger and rounder buttocks”.

Other publishers have also appeared to want to cash in on the craze, as a third book featuring hamuketsu will be published at the end of May.

The book, which will be published by Arimine Shoten Shinsya Co, will be called Ganso Hamuketsu (The Original Hamuketsu).