Military Chess-Tactical Strike

That day in Jinling, the sky was ominously dark, roiling clouds heavy as spilt ink, pressing down until one could barely breathe.
Suddenly, a thunderous roar echoed from the distant horizon, like the wrath of the sky god. But listen closely—was that thunder?
No. It was the bombing fleet of the Crimson Eagle Army, a menacing black mass flying in from the Eastern Sea, descending upon this thousand-year-old city like a flock of vile vultures.
At the end of Zhuque Avenue stood the Eastern Army Military University. This institution had long been the cradle of Eastern generals—many famed commanders, engineers, and firearms experts had emerged from its halls.
Among its students was a young man named Kaleb. His family was poor, and he had only gained admission through a military tuition waiver.
Usually quiet and reserved, his grades were unremarkable; he barely passed most subjects. Yet he possessed a rare gift for military strategy and history.
When wargaming tactics, he often produced startlingly unexpected maneuvers—if no rules were imposed, even the professors had never once beaten him in a simulated contest.
That day, Kaleb was studying in the underground library with his two close friends. One was Andy, exceptionally brilliant, a master of tactical command admired by everyone on campus, known as the 'Prodigy of Jinling.'
The other was Sarah, the only daughter of General Lee, the 'God of War of the Eastern Army.'
Beautiful and spirited, she excelled in explosives and mechanical engineering, commanding universal respect—and secretly, the admiration of countless suitors.
"This question—'The city is besieged, supply lines are cut, reinforcements have not arrived. What should be done?'… How would you answer?" Kaleb closed the heavy volume Eastern Battle Strategies, his brow furrowed.
Andy's brush paused, an ink drop blooming on the paper: "If we defend to the death, we die for certain.
Better to set fire to our own camp at night, feign a rout, and lure the enemy into the city for street fighting—risky, but it might buy a slim chance of survival."
"Too ruthless," Sarah looked up, her fingertips still stained with black residue from testing gunpowder. "But what if the enemy refuses to enter the city? What if they'd rather flatten the whole place than get tangled in the alleys?"
Andy smiled bitterly: "So this question has no solution. No perfect score this time."
Kaleb was silent a moment, then said slowly: "Passing is good enough. If you get perfect scores every time, you leave no room for improvement."
Sarah shot Kaleb an exasperated look: "Can't you show some drive, you lazy bug?"
The three were chatting as they studied when suddenly, the sky and earth split apart—bombs were falling!
The shockwave threw them to the ground. Their ears rang as if a thousand drums were pounding. When they struggled to their feet, they saw that the entire university had been reduced to scorched ruins.
Had they not been in the underground library, they would have perished in the inferno alongside their classmates and teachers.
They staggered outside to find streets strewn with corpses and the air torn with anguished cries. Jinling was destroyed; the Eastern Army University was gone. The three fell to their knees weeping."