Collect all 3 Naruto cards and receive the 4th special card at one of the SHONEN JUMP Tournament locations.
You can only get this fourth card by attending a SHONEN JUMP Tournament and bring these 3 promo cards that can be found in:
Promo Card #1: Naruto CCG Series 17 hobby booster boxes
Promo Card #2: Naruto Graphic Novel Vol. 48 in June 2010
Promo Card #3: SHONEN JUMP August Issue in July 2010