Rilakkuma (リラックマ Rirakkuma, a combination of the Japanese pronunciation of relax and the Japanese word for bear -kuma- ) is a Japanese character designed by Aki Kondo, produced by San-X in 2003.
Rilakkuma and Tarepanda, another San-X character, have been described as "huge hits in Japan" by The New York Times. As of May 2010, Rilakkuma ranked as the fifth most popular character in Japan in a survey of the Character Databank.
The San-X company puts staff members under obligation to create one cute character per month. Aki Kondo (also the creater of Okutan to Dannachan) saw a TV show about dogs. She wished to own a pet because at that time she was very busy working and hoped for a more relaxing life. Rilakkuma is an embodiment of her wish.
In July 2009, Bandai released an exclusive edition of Rilakkuma-themed notebook computers.

Rilakkuma mysteriously appears in the female office worker Kaoru's apartment one day. He is a soft toy bear who has apparently decided to take up residence there. On his back is a zipper which when opened reveals a light blue polka dot patterned material. The reason for the zipper on his back is unknown.
He was first seen in a series of picture books called Rilakkuma Seikatsu produced by San-X but since has become equally popular as a soft-toy character. In the picture books, he is often seen dressed up in a variety of costumes such as a kappa costume. In addition, it is implied that even in his usual appearance, his entire lower body is a costume, which he will often replace when it gets old or dirty (Rilakkuma is frequently seen sitting around waiting for suits that look exactly like him to dry on the clothes line). However, it is not clear whether his head is also part of his costume.
His favorite foods are dango, pancakes, omurice, and custard pudding. True to his name, he enjoys relaxing and his favorite things include sleeping, lying around, watching television, listening to music and soaking in hot springs. He loves using Kaoru's yellow bean bag pillow, although there has been some controversy whether or not the yellow bean bag pillow is in fact Kiiroitori. Despite some confusion that often occurs relating to Rilakkuma and his friend Korilakkuma's genders, it is stated on the San-X site that he is in fact a male, while Korilakkuma is indeed female.
Rilakkuma is often accompanied by Korilakkuma, Kiiroitori named her Korilakkuma because she looks like a small Rilakkuma (Ko means small or little in Japanese). She also mysteriously appeared at Kaoru’s house. Rilakkuma didn’t know her at the time. She is full of vigor and is very mischievous. Kiiroitori, a yellow chick who lives at Kaoru’s house. Kiiroitori means “yellow bird” in Japanese. He used to be in a birdcage but now he comes out at his own discretion and scolds Rilakkuma and Korilakkuma because Rilakkuma is too lazy and Korilakkuma is too mischievous. Sometimes he feels down because he thinks he scolds them too much. He plays a tsukkomi role (considered to be the smarter, more logical one who criticizes others for making mistakes). Kiiroitori is basically the opposite of Rilakkuma because of the bird's hard-working nature and love of cleaning. Kiiroitori is Kaoru's pet chick. Korilakkuma frequently plays pranks on Rilakkuma while he is sleeping, such as drawing on him, putting headphones on him and sewing odd color patches on his bear suits. Most of the time, Korilakkuma doesn't say a word, but sometimes she imitates what Rilakkuma is saying.
Korilakkuma also has the appearance of a bear, but also has a red button attached to her chest, and so it seems that she is also not a real bear. However, unlike Rilakkuma, she doesn't have a zipper on her back. Her favorite foods are strawberries, apples and cherries and she loves playing with her radio controlled duck. Like Rilakkuma, she also likes listening to music, particularly at loud volume using her music player.

I would say japanese are obsessed with Rilakkuma & co. because you can find anything (and I'm not joking while I say ANYTHING) in Rilakkuma shape or with his brand. It's crazy, not only that you can also happen to meet them in some Rilakkuma-stores or in the streets.


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Source @ wikipedia.