Seki-kun: The Master of Killing Time

Tonari no Seki-kun (となりの関くん?) is a Japanese manga series written and illustrated by Takuma Morishige. Originally published as a one-shot in 2010, it started serialization in the November 2010 issue of Media Factory's Comic Flapper magazine. An anime DVD was released bundled with the limited edition of the manga's fifth volume on January 4, 2014, and a television series adaptation began airing in Japan on January 5, 2014.

Plot
These are the observations by Rumi Yokoi of her classmate, Toshinari Seki, as he plays incredibly elaborate games at his desk and somehow never gets caught in the process.

Official

 * Web Site Official

Other Sources

 * Tonari no Seki-kun on Wikipedia