Kei Takahashi

Standard	Rotated out on April 23, 1997
Pioneer	Not Legal
Modern	Not Legal
Legacy	Never Banned
Vintage	Unbanned since November 1, 1995
Commander	Never Banned
Pauper	Never Banned
Oathbreaker	Never Banned
Extended	Rotated out on October 1, 1999

View on Scryfall

Timeline

• June 1, 1994 - Released
• August 1, 1994 - Status changed to Restricted in Vintage
• November 1, 1995 - Status changed to Unbanned in Vintage

Rationale

In 1994, all Legendary permanents were restricted for flavor reasons. Kei Takahashi was restricted to one copy as a result. This ruling has since been lifted.