War movie in which the countries sent one soldier to fight each other instead of entire armies. Took place on an island and I don't believe they had weapons. During the movie the countries sent an additional soldier to help the first one win the fight. This was against the rules of engagement and the original combatants killed their own ally out of respect. The winner was supposed to send a radio signal back to the two countries with code that identified who had won. It ends with both soldiers dying on the beach and one of them pressing the transmitter but unable to send his code before dying therefore neither side knew who had won. I know one soldier was American and I think the other was Japanese?? I saw this on TV as a kid in the 70's.

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.