According to people at the scene, Kazuki -- the eventual inspiration for the "Yu-Gi-Oh!" trading card game -- dove into a riptide in hopes of bringing a woman and her 11-year-old daughter back to shore on July 4.
Major Robert Bourgeau, a 49-year-old U.S. Army officer and scuba diving instructor, also took action ... and while he personally did not encounter Takahashi during the rescue mission, multiple people say they saw the artist attempting to assist.
Bourgeau managed to save the 11-year-old girl and the mother ... but when he went to help a 39-year-old U.S. soldier who was also struggling in the water, he feared he would lose his life if he went on any longer.
Thankfully, Bourgeau was able to help yell orders to help the soldier navigate out of the rough waters.
Kazuki's body was found about 1,000 feet offshore two days later.
Bourgeau called Takahashi a "hero" ... saying, "He died trying to save someone else."
Bourgeau was nominated for the Soldier’s Medal for his actions ... an award given to those who execute heroic acts that do not involve an enemy.