|Common name||Windows 3.1-kun|
|Also known as||Windows 3.1, Janus-kun, Bombay-kun, Sparta-kun|
|Height||*none listed officially|
|System personified||Windows 3.1|
|Debut||6 Apr 1992|
|Latest release||3.11, December 31, 1993|
Windows 3.1 was the direct successor to Windows 3.0. 3.0 began life in 1989 when a batch of programmers for Microsoft decided to cobble together a protected-mode Windows as a side project. The company executives liked the project, and improvements such as the first stirrings of multitasking, the Program and File Managers, Protected Modes, and Solitaire. 3.0 was also the first with 16-bit capabilities, and was released on May 22nd, 1990. 3.1 took these features and improved upon them, including adapting the later 3.0 version Windows 3.0 with Multimedia Extensions 1.0. 3.1 also began supporting 32-bit applications, but due to this dropped one of the protected modes introduced in 3.0 (the "real" mode). 3.1 was more stable over its earlier form, crashing less and supporting greater colours, more detailed icons that could be dragged and dropped, and multimedia support. 3.1 was also the first Microsoft OS to be available on CD-ROM, and have versions available in foreign languages (such as Cyrillic characters, Kanji, and Simplified Chinese).
3.1-kun is an older man with a serious demeanor. He dresses in green (or sometimes blue, or 3.1-tan's lilac) Meiji-era Military regalia with a "3.1" medal on the right side, suggesting that he might have had a hand in the OS-tan Wars. Despite the look of him, not much can be said about his nature other than he is serious, stoic, and enjoys things usually associated with Japanese elders, such as rice crackers and tea. Like his sister/counterpart 3.1-tan, he has a DOS companion, but unlike her his is a humanoid, not a cat. 3.1-kun's DOS Catgirl is usually shown by his side in some form, sometimes the size of a 13-year-old girl, sometimes the size of a housecat. She typically takes part in the activities that he does, such as leisurely crackers and tea. Though it is not shown, it is possible that 3.1-kun might like games, especially those of strategy (Go, Shogi, Reversi). He might also like card games (such as Solitaire or perhaps even Hanafuda). Although they have been lost to the internet, there were depictions of a younger 3.1-kun. Typically these show him with silver hair a bit longer than OS9-kun, his usual military top, but with a cape and military-type cuffed shorts. He also sports a military beret and an armband with the Windows logo on it in a circle (cocked upward into a diamond; may also have been replaced with a swastika in one picture. It should be noted that often times the Japanese don't realize the implications of imbuing that symbol into their artwork, as some of the country just doesn't know what went on in the European Theatre during WWII, dealing with their own issues in mainland Asia and the Pacific). His expression in most of his younger pictures is less "serious, wizened man type" and more "mischievous, patriotic teenager type". His outfit in these pictures has always been lilac, like his sister. Overall, 3.1-kun isn't shown much in the fandom, rendering he and his personality a bit of a mystery. Given that he doesn't antagonize other OSes, either he has settled into a comfortable retirement or his years of fighting have contributed to a knowledge that yearns for peace. We'll have to wait and see.