War movie where the two sides sent a single soldier to fight each other instead of entire armies. Took place on an island and I don't believe they had weapons. More of a guerilla warfare theme. During the movie the two sides sent an additional soldier to help win the fight. This was against the rules of engagement and these helpers were killed by their own man out of respect for the enemy to fight fair. The winner was supposed to send a radio transmission along with a code identifying who had won. The movie ends with both soldiers dying on the beach. Just before dying one presses the transmitter sending the signal but without the code so neither side knew who had won. I saw this on TV as a kid in 70's. One soldier was American and I think the other was Japanese??

This is a failed TV pilot from 1970 called The Challenge, which was written by Marc Norman in his professional debut. Twenty-eight years later, he penned Shakespeare in Love with the acclaimed Tom Stoppard. Given that his script immediately prior to that had been the notorious bomb Cutthroat Island, I think we can credit Stoppard with most of the success here. At any rate, The Challenge stars the incomparable Darren McGavin, along with Broderick Crawford, Mako, James Whitmore, and Sam Elliott in one of his early roles.