A split zine is a zine written by more than one author. Generally a split zine combines two existing or new zines in one issue. When reading the zine from the front, the first half is one zine, at the halfway point the text is upside-down, by flipping the zine over and reading it from the back side, you can read the other zine in the split issue. Other techniques have also been used.
Split zines may be utilized for various reasons, including sharing photocopying costs and distribution, partnering up with a friend to collaborate on a project, or when two zinesters write about similar subjects.
Possibly the first split zine was Futurian War Digest. published during the years of World War II in England. Due to various war measures and lack of resources, it was stapled together and distributed with over twenty other various zines and distributed with them.
When more than two authors are involved, the resulting work is usually referred to as a compzine.