User summary and from Japanese Wikipedia:
KCEJ was the first of the 5th Osaka development studio at Konami, and they went independent in april 1996. As the former Kobe studio of Konami had gone independent in 1994 and called themselves Konami Osaka, the 5th Osaka studio named themselves KCEJ – Konami Computer Entertainment Japan. They settled themselves in Ebisu in Tokyo.
This was the studio that Hideo Kojima of Metal Gear fame belonged to, and later formed Kojima Productions. In 2003, both studios moved to Roppongi Hills.
- In 1998, Konami Computer Entertainment Japan (KCEJ or KCEJ West) merged with Konami Computer Games Aoyama (KCGA) to become KCEJ East.
- In 1999, they took over the running of Konami Computer Entertainment Shinjuku (KCE Shinjuku)
- In 2000, they merged with Japan Business Consultants.
- In 2001, their abbreviation changed from KCE Japan to Konami JPN.
- In 2002, they entered the JASDAQ stock market.
- In April 2005, they were merged into Konami.