|Full Name||Citation needed|
|Debut||1985-11-20 (OS) 2007-02-12 (character)|
|Hair color||Usually brown|
|Eye color||Usually brown|
This is an article about the 1.0-tan OS-tan. To learn more about the OS she personifies, or see more characters that personifies that OS, see Windows 1.0
1.0-tan (Japanese: 1.0たん, 1.0-tan), also known as Oichi (Japanese: お壱), or Citation needed, is the OS-tan that depicts Windows 1.0x. She is one of the lesser known OS-tans.
She is the matriarch of the Windows OS family and shown as the sister and friend of 3.1-tan. Her hobbies are Origami and Reversi, but however, because she was unable to stack windows on top of each other (You could not stack windows in Windows 1.01) she had to arrange them like origami, and she was often introduced in screen shots. She normally wears a kimono, but 3.1-tan has her wear strange outfits. Her favorite food is tsubuan (bean jam) yokan.
Being born in the Showa period (Windows 1.01 was released in the Showa period in Japan), she is retro, and profoundly nostalgic, but she is usually confused by the gap between past and present.
If and when she is angered, she can produce laser beams from her eyes.