Seiji Sakaguchi
Jan Wilkens toured New Japan Pro-Wrestling in 1973 with fellow Bronco Universal Promotions regular Manie van Zyl as part of the NJPW "Big Fight Series". On 2 April 1973, in Ōita, Japan, Wilkens teamed up with Jozsef Molnar to lose to Seiji Sakaguchi and Kotetsu Yamamoto. On 7 April 1973 in Fukushima, he teamed up with Molnar and lost to Seiji Sakaguchi and Osamu Kido. On 12 April 1973 in Sendai, Wilkens teamed up with Manie van Zyl, losing to Seiji Sakaguchi and Kotetsu Yamamoto. In his final match with New Japan Pro-Wrestling on 18 April 1973 in Osaka, Jan Wilkens lost to Antonio Inoki in a singles match in 20:12 when Inoki made him submit to the Octopus Hold.