[Ribons Nights (Kyouno Aki)] Kawashiro-sanchi no Shimai

Schoolgirl uniform (セーラー服, sailor fuku / 制服, seifuku) is a costume tag that's deeply embedded in Japanese manga and doujinshi culture. It refers to the iconic Japanese school uniforms — either the sailor-style (sailor fuku) or blazer-style (seifuku). This tag is significant because school settings are a common backdrop for many genres, from romance to fantasy. The uniform itself has aesthetic appeal in illustration, and artists often use it as a visual shorthand for youth and innocence. It frequently appears alongside 'lolicon,' 'sole female,' and various school-themed parody tags.

Mosaic censorship (モザイク) refers to the pixelation or blurring applied to explicit content in Japanese published works. This is due to Japanese obscenity laws that require censorship of genitalia in published materials. The tag helps readers identify whether content is censored or uncensored. Many doujinshi are published with mosaic censorship and later 'decensored' by fans or released in uncensored versions by the artist. Related tags include 'uncensored' and 'full censorship.'

Sister (姉妹/お姉さん) refers to content featuring sister characters. This tag covers both older sisters (ane) and younger sisters (imouto). It's commonly paired with 'incest' for blood-related scenarios or can stand alone for step-sister or non-related sister figures. The tag is one of the most common character relationship tags in doujinshi.