The Greatest 18 Championship was championship in the New Japan Pro Wrestling promotion which was intended to complement the IWGP Heavyweight Championship. The Greatest 18 Championship was represented by the former Martial Arts Championship and was awarded to Riki Choshu in 1990. Choshu lost the title to The Great Muta in 1992. Muta retired the title on September 23, in order to focus on his IWGP Heavyweight Championship title defenses. The title was subsequently officially retired by NJPW.