Marines are taught from boot camp on the basics of the laws of war — like when to safeguard civilians or how to manage prisoners.

But the battlefield isn’t as clear-cut as a Geneva Conventions text, so a unit of Marine Reserve officers is making a sweep through Japan to help leaders and rank-and-file Marines make better decisions.

The main thrust of the visit is a three-day graduate-level training for noncommissioned and commissioned officers that includes lectures as well as scenario-driven, small-group discussions “to develop an understanding of the finer points and nuances of the laws of war,” said Maj. Frank Campbell, an instructor.

With an understanding of the underlying principles, leaders will be better prepared to make decisions under difficult circumstances, Campbell said. He gives the example of Marines coming under fire from a sniper in a building. Without knowing if civilians are inside the building, the appropriate reaction isn’t obvious.

“What would be a good textbook response?” he asks. “It’s a lot more difficult to execute these scenarios, even in simulated combat.”

The training coincides with an investigation into 24 civilian deaths in November in Haditha, Iraq, for which a group of Marines stand accused. But it wasn’t a reaction to the incident nor does it focus on that issue, Campbell said.

“I think some people expected our class was a knee-jerk reaction to Haditha,” he said. “I was concerned students would ask Haditha-based questions, but that hasn’t happened.”

The annual training was planned before the Haditha allegations arose, Campbell said. And although he expected questions in connection with the case, Marines have focused on circumstances they might personally encounter rather than investigations at large, he said.

The laws of war are based on the Geneva Conventions and concern, among other things, the safety of civilians in combat, the treatment and care of prisoners of war, and the protection of cultural resources such as a mosque.

The training encourages leaders to plan for circumstances such as taking prisoners while completing a mission, so Marines never have to choose between following the rules and completing the mission, he said.

During the training, Campbell said, participants raised questions about the recent Supreme Court decision that allows prisoners in Guantanamo Bay, Cuba, to challenge their detainment.

The case, Campbell said, doesn’t affect Marines on the battlefield, since a servicemember’s responsibility at that level is to offer all combatants safe and humane treatment, not to worry about their status — which is decided farther up the chain.

In addition to the three-day program for leaders, the instructors are offering a two-hour training for junior Marines.

At Marine Corps Air Station Iwakuni, two of those lectures will be offered Thursday for E-5s and below at the Station Chapel at 9 a.m. and at 1 p.m.

The instructors — from the Laws of War Unit based at Henderson Hall in Washington, D.C. — visit Marines in Japan annually. After a brief stop at Camp Fuji this month, they spent a week on Okinawa training about 1,000 Marines before arriving in Iwakuni this week.