From Japanese Wikipedia and English Wikipedia:
Raizing (pronounced like "Rising") was a Japanese developper, famous for their shooting games. They were founded in March 1993, together with the sibling company Eighting (also known as 8ing), primarily from staff of the arcade developer Toaplan after they closed their doors. They were one of several, along with Cave, Takumi, and Gazelle, all of which were noted for their strong support of the shoot'em up genre, and the "danmaku" (or "bullet hell") subgenre in particular. Raizing continued to use arcade hardware based on Toaplan's units for years after Toaplan's demise.
Due to their siblingship with Eighting, some games are credited to "8ing/Raizing".
Shortly after founding, a handful of former Compile employees entered Raizing, mainly those who worked on Musha Aleste, including Yuichi Toyama (AKA "Healthy Toyama").
Sorcer Striker, Terra Diver and Battle Garegga are among their most famous shoot'em-ups .
In October 2000 they merged with Eighting, and disbanded. Shinobu Yagawa, designer and programmer of a number of Raizing shooters including Battle Garegga and Battle Bakraid, is now employed by Cave.