After Marcos Cardenas becomes a casualty of war during Hillsdale High School’s annual “Battle at Dawn” simulation, a parent volunteering as a Red Cross worker gives him a black wristband and writes an “x” on his paper dog tag. The San Mateo, Calif., school has had students participate in the simulation for more than 20 years. (James Regan/James Regan)

SPLAT! I was startled when a round from the 6th Bavarian Reserve Division landed at my feet. Fortunately, it was a water balloon. This was not the real Battle of Neuve Chapelle, waged 103 years ago.

The clash of Germans and Britons that ended with 21,000 casualties on that World War I field was being simulated by shivering Bay Area ninth-graders in jackets, jeans, tights and bicycle helmets. They were pretty fierce with their water weapons at 6:50 a.m., when they otherwise would have been in bed ignoring parental pleas to get moving.

The annual Hillsdale High School “Battle at Dawn” is the most daring and involving high school project I have ever encountered. (If you know of others, my email is above or below.)

I wish such compelling approaches to social studies and English were more common. The battle has survived some hostility (it is teaching war; it is too much about dead white males) because parents and students love the combination of engagement, equity and rigor.

Social studies teacher Greg Jouriles designed the idea with colleagues Susan Bedford and Karen Dresser in 1994 and still facilitates it with English teacher Christine Crockett and the rest of the ninth-grade humanities faculty. The battle was, at first, just for honors students but now involves the entire freshman class and has brought other reforms. As a Hillsdale alum, I am amazed at what imaginative educators are doing for my old school.

In 1962, I broke my left arm playing tackle football with friends near what later became the mock battlefield on the south side of the sprawling campus. Injuries from the World War I simulations have been much less serious. This time, the field was littered with bodies only because parent and faculty monitors told students to play dead when they had been hit. They still had to keep their eyes open. Their after-battle reports were soon due.

Hillsdale’s demographics are 17 percent low income, 39 percent white, 29 percent Hispanic, 22 percent Asian/Pacific Islander, 1 percent black and 11 percent multiethnic — a not atypical California suburb. But its teaching style has become very different.

David Weiskopf, father of ninth-grader Ben Weiskopf, sees much change since he attended Hillsdale 40 years ago. “The school is clearly focused not just on teaching, but on the kids learning,” he said.

To facilitate teacher cooperation in the humanities, the ninth and 10th grades are divided into four houses named after the ancient cultural centers of Florence; Kyoto, Japan; Marrakesh, Morocco; and Oaxaca, Mexico. Students meet daily in small advisory groups. All seniors — as if they were graduate students — take oral exams on their overall studies, with some questioned about writing projects or others about documents they have been assigned to review.

The freshmen must do a two-part autobiography of their battle character. They read “All Quiet on the Western Front,” much poetry and history. They plan tactics and accumulate weapons. The variety of Super Soakers would make a Hasbro sales rep weep with joy. Filled balloons have to be transported in tubs of water to avoid collapsing under their own weight.

Unlike 1915, only half of the soldiers are male. Teachers selected females this year to lead both armies — British Gen. Hadeel Eljarrari and German Gen. Kelly Wong.

“We are the British, mighty, mighty British,” sang one squad heading for the battlefield. But they lost. During 20 minutes of watery mayhem, the British 1st Army never broke through the plywood-fronted German lines. “The entire plan the officers created didn’t get communicated well,” British Capt. JT Waugh said. In the real battle, the British had some early success but lost those gains.

The dead at Hillsdale were not allowed to speak the rest of the day to reinforce the consequences of war. “Mr. J!” said an excited British private to Jouriles. “I got there. I was the only one to cross the line!”

“So you died, Lorenzo?” Jouriles asked gently. “Yeah,” he replied.

The teacher put a finger to his lips. Lorenzo Hernandez had to be silent while he wrote his reports. I suspect teachers elsewhere have similarly intriguing ideas, if their schools would dare to let them try.