The incident of an American led Kachin detachment crossing the border into China to retaliate against Chinese troops was experienced by Chamales himself.
Chamales was a member or Merrill's Marauders, and when that unit was disbanded he joined the OSS and was in Burman until the end of the war. If you read Chamales' book you'll see a disclaimer in the front more or less to the effect that the author had personal knowledge of the events as described when the main character is brought to account for his actions. In the real incident, Chinese troops killed Kachins rather than Ameicans, and it was their idea go cross the border for revenge. For further reading I suggest "BEHIND JAPANESE LINES: WITH THE OSS IN BURMA" by Richard Dunlop, where this incident is mentioned.
"In the real incident, Chinese troops killed Kachins rather than Ameicans". This makes more sense. When I read the plotline, my first reaction was that Chinese killing Americans, when the Americans were there to fight the Japanese, made no sense. Typical Hollywood nonsense. They can't even come up with a story that makes sense.
No, not off base at all . . . one has to first understand the intricacies of World War II--the real World War II . . . the US was forcing Chiang into an alliance with Mao--Communist forces . . . many warlords opposed this . . . so they sold and traded with the Japanese (who were blocking off a Commie take over of China) . . . US forces would be attacked by said warlords . . . all of this is part of the, shall we say, "dirty little secrets" of Chamales book . . . one of the only books to deal with the real truth of the situation . . .