|Voiced by||Kenichi Ogata (JP), Steve Kramer (EN) ((The Adventures of Mikuru Asahina Episode 00)), Michael McConnohie (EN)|
Shamisen first appears in The Sigh of Haruhi Suzumiya, in which Haruhi picks Shamisen from a park of stray cats to be the character "Yuki"'s familiar. Kyon notes that Shamisen being a male calico cat is itself unusual, a 1 in 3,000 chance requiring the cat to have Klinefelter's syndrome.
Haruhi is the one who decides to name the cat Shamisen. Shamisen is later nicknamed Shami by Kyon's little sister.
When Haruhi begins to confuse the fictional world with reality, Shamisen begins to talk in a deep baritone voice, and the Brigade is forced to keep this from Haruhi. Kyon has a conversation with Shamisen, in which Shamisen's comments are almost entirely moralistic and philosophical, and Kyon convinces Shamisen not to talk in front of Haruhi (or "that girl", as Shamisen refers to her). He does however make one comment in the movie The Adventures of Mikuru Asahina Episode 00, forcing Yuki to disclaim it as ventriloquism. Shamisen purportedly loses his ability to speak when Kyon separates fiction and reality in Haruhi's mind. By the next year, Kyon had not heard the cat speak.
Kyon thus adopts Shamisen, and Kyon's sister thus takes a liking to him. Shamisen is often seen in "slice-of-life" moments in Kyon's life, especially when he wakes up or before he answers the phone. Following the movie incident, Shamisen became an exceptionally well-behaved housecat, never acting like a stray, and often acting more intelligent than a regular cat.
During The Disappearance of Haruhi Suzumiya, Kyon in a mad fit of rage tries to get Shamisen to talk to prove he still has a connection to his original world; Shamisen however remains silent. According to Kyon's sister, in this reality Shamisen is being looked after by Kyon for an unspecified friend who is abroad.
In Snow Mountain Syndrome, when Kyon commented that he didn't want to take care of a talking cat, Nagato examined Shamisen for 30 seconds and then said "no need". Shamisen plays a semi-important role in "Where Did the Cat Go?" in which he is the key to solving the "murder" case. He is swapped with a female calico cat in order for the "murderer" to hide his identity. To avoid confusion, Koizumi often referred to the original Shamisen as "Shami-One" (シャミ壱 Shami-ichi).
Shamisen was used to house data organisms in Wandering Shadow. They had previously been infesting dogs, making them sick. Nagato placed the organisms in him and then "froze" them within him, as the cat was a more suitable "interface" for the organisms than the dogs. In The Dissociation she asked Kyon how the cat was faring. Kyon said that he was energetic and no longer talking—normal.
- He briefly appears in episode one of The Melancholy of Haruhi-chan Suzumiya. When Kyon arrives home, his sister, angry that he was with his friends again, is seen holding an unconscious Shamisen, telling Kyon that Shamisen was forced to play with her all day until he collapsed from exhaustion.
A shamisen is a three-stringed musical instrument similar to a guitar, originating in Japan. A shamisen is usually made of cat or dog hide, so calling a cat "shamisen" is analogous to a Westerner calling a cat "tennis racket."