Iron Coffin

"Every time they underestimated East Asia, Ma Chongshan's chair moved an inch closer to the 811 Institute."

Twelve days later, the old man's chair had been moved to the testing grounds.

April 26, C.E. 71. 811 Institute Comprehensive Testing Grounds, North Open Area.

Three Black Iron units stood side by side on the concrete apron. Unit One was the repaired prototype, its right arm joint replaced. The chest armor still bore an unpolished crater left by a seventy-six-millimeter machine-gun round from its first battle. Units Two and Three had fresher paintwork, with neatly edged dark gray Ceramic Steel external plates and sealant strips at their joints still free of dust.

Han Zheng stood beneath Unit One's feet, looking up as the pilots of the other two machines climbed the boarding ladders.

Unit Two's pilot was Tian Mu, twenty-eight, a sergeant from the Third Regiment of the East Asian Armored Ground Forces. He had driven tracked main battle vehicles for six years and had never touched a Mobile Suit before being transferred to the 811 Institute. His arms were as thick as calves, and he climbed the boarding ladder as nimbly as if scaling a tank's side skirts.

Unit Three's pilot was Liu An, twenty-five, a corporal from the same regiment. His file listed him as an armored communications specialist, but during exercises he had filled in for injured tank commanders twice and achieved the regiment's third-best annual shooting score. He stood half a head shorter than Han Zheng, but his hands were just as broad.

"Tian Mu, have you set the comm channel?" Han Zheng called from the ground.

Tian Mu's voice came from Unit Two's cockpit, muffled as though he were speaking from inside a barrel.

"Set. I ran Jiachen's auxiliary interface through the simulator three times last night. The ballistic correction prompts show up in green in the lower left corner. But when that tactical recommendation window pops up, it blocks my view to the right. Can its position be adjusted?"

"No. Zhou Boyuan fixed its placement. Changing it would affect the order in which you read the information."

"Then I'll put up with it."

"If you can't, don't look at it. Listen instead. Jiachen will repeat critical orders verbally."

Over by Unit Three, Liu An was much quieter. He merely reported over the channel that he was ready.

The observation area had been set up atop a concrete bunker on the eastern side of the testing grounds, with a view covering the entire northern open area. Ma Chongshan sat in a folding chair beside his adjutant and two staff officers. Sheng Lan monitored the pilots' vital signs in the bunker's ground-floor control room.

Lin Yuan stood at the edge of the bunker roof, one hand resting on the concrete parapet.

"Chief of Staff Ma, today's exercise is a coordinated advance using crossfire from three units. The simulated enemy consists of six ZAFT Ginn-type MS units. Battlefield data will be generated in real time by Machine Soul—Jiachen and projected onto moving targets in the exercise zone."

Ma Chongshan did not look at him. His gaze remained fixed on the three dark gray machines on the apron.

"Live ammunition?"

"Low-charge exercise rounds. Their detonation characteristics match combat rounds, but their lethal radius has been reduced to within the safety zone. Target destruction will be determined by Jiachen's sensor array."

"Begin."

Lin Yuan pressed the comm switch.

"Han Zheng, begin."

The plasma-assisted power systems of the three Black Iron units activated at once. Their hum spread across the apron, making the water in the cups on the folding table atop the bunker ripple with fine waves.

Han Zheng's voice came through the channel.

"Formation, arrowhead. Eighty-meter spacing. Tian Mu on the left flank, Liu An on the right. Advance at fifteen meters per second."

The way the three machines stepped forward was completely different from the light, gliding stride of a Short Sword. Their heavy feet slammed into the concrete, each step sending faint tremors through the ground. The weight of their sixty-millimeter Ceramic Steel external plates kept their joint actuators groaning under continuous load.

One of Ma Chongshan's staff officers muttered under his breath.

"They move like bulldozers."

Ma Chongshan did not respond.

Eight hundred meters ahead in the exercise zone, six moving targets activated simultaneously, darting about with the movement patterns of Ginn-type MS units. Two cut in from the front, two swung around the left, and two around the right.

Han Zheng's voice command and Jiachen's tactical prompt arrived almost at the same time.

"Tian Mu, the two on the left are yours. Keep your firing arc between ten and eleven o'clock. Don't chase them. Block their route."

Tian Mu raised his Bombard Gun noticeably slower than Han Zheng would have. It took him nearly two seconds to steady the muzzle over the target sector. By the time he fired his first shot, the targets had already passed the optimal hit window.

The exercise round exploded twelve meters behind the target. Miss confirmed.

"Off target." Tian Mu's voice carried the sound of gritted teeth.

"Don't follow the shot. Watch the next predicted point Jiachen gives you." Han Zheng kept his voice steady.

Tian Mu shifted his gaze to the lower left of his tactical display. A new line of green ballistic correction data refreshed. He adjusted the muzzle angle and fired the second round.

Hit. The sensor on the target's surface lit up with a red confirmation light.

But trouble broke out on the other side.

The two targets on Liu An's right flank chose a high-speed crossing pattern, their paths repeatedly weaving through Unit Three's firing arc. Liu An fired twice, missing both shots. When he fired the third, the Bombard Gun's recoil threw the right side of the machine off balance. Unit Three's right foot slipped beyond its position line, and the entire machine tilted fifteen degrees to the right.

One of Ma Chongshan's staff officers spoke up.

"The formation's broken."

From the control room below the bunker, Sheng Lan's voice cut into the comm channel.

"Unit Three's posture has shifted. Torque feedback in the pilot's right wrist has exceeded the limit."

Han Zheng did not turn back to attend to Liu An. Instead, he issued an order over the channel.

"Liu An, abandon the pursuit. Lock your muzzle on the forty-five-degree sector directly ahead. Don't fire, don't retract. Just hold it."

Liu An's voice was muffled.

"Understood."

Unit Three stopped its tracking fire and braced the Bombard Gun at a fixed angle. The load noise from its joint actuators subsided. The two targets tried to circle in behind from the right flank, but the moment they entered Unit Three's firing arc, their trajectories were forced to shift. They could never complete the encirclement.

Han Zheng used that opening to turn. Unit One's Bombard Gun fired twice in succession, covering the movement paths of the frontal targets. Both confirmation lights turned red at once.

Tian Mu followed up by taking out the second target on the left flank.

The remaining two targets on the right circled outside Liu An's blocking sector three times, never finding an angle to break into the core. Finally, Han Zheng adjusted the formation. The three Black Iron units closed their spacing to form a dense field of fire, and six simultaneous shots covered the targets' final movement paths.

All six red lights illuminated.

The exercise had taken four minutes and twenty-seven seconds.

Ma Chongshan rose from his chair, not because he was excited. He walked to the edge of the bunker, placed a hand on the parapet, and looked down at the three Black Iron units standing below.

Unit One did not move an inch. Unit Two's muzzle dipped slightly; Tian Mu was probably wiping sweat inside the cockpit. Unit Three still leaned to one side, and the position of its right leg had yet to be fully corrected.

"Director Lin."

"Chief of Staff Ma."

"What did your Unit Three pilot drive before this?"

"Tracked main battle vehicles. A communications specialist and temporary tank commander."

"No wonder he can't stand steady. Tank crews are used to relying on the chassis's center of gravity to offset recoil. A Mobile Suit's center of gravity is above the waist. He tried to absorb the Bombard Gun's impact with a tank driver's instincts and overcompensated in the opposite direction."

Lin Yuan did not reply.

Ma Chongshan turned around.

"I understand your formation fire-coverage concept. You're not pursuing individual-unit accuracy. You overlap the firing arcs of three machines to create a blockade zone, forcing enemy units into a predetermined kill area. Not a bad idea."

He raised three fingers.

"Three problems. First, today's targets were set to Ginn-type movement parameters, with a top speed of two hundred kilometers per hour. If you replace them with ZAFT commander units and double that speed, can your blockade zone close in time?"

"Jiachen's fire-control response time is 0.08 seconds. Human aiming can't keep up, but AI ballistic correction can compensate."

"Second, ammunition consumption. You fired twenty-two rounds in four and a half minutes against six targets. An average of 3.7 rounds per target. In combat, each machine carries forty rounds, one squad carries one hundred and twenty. At this rate, you'll be dry after two waves of enemies. How will logistics keep up?"

Lin Yuan looked toward Sheng Lan. Her voice rose from the control room.

"The ammunition reload plan is already scheduled. Fang Heping designed a quick-release ammunition feed box. Estimated battlefield replacement time: ninety seconds."

"Ninety seconds." Ma Chongshan turned the number over in his mind. "On the battlefield, ninety seconds is enough for the other side to make a round trip."

"That's why they need fixed positions," Lin Yuan said. "The Black Iron Squad's tactical design is not for independent maneuvering. It is meant to operate alongside defensive lines. Advance to predetermined positions, establish a fire-coverage zone, and wear down the enemy's effective strength."

Before lowering his third finger, Ma Chongshan glanced at Unit Three's crooked stance in the distance.

"Third problem. Your three pilots today consist of one test pilot and two tankers. This makeshift lineup fought six targets, and Unit Three nearly fell over on its own. Once you mass-produce them, the people going to war will be even more varied, with even greater differences in ability. How large a gap in pilot skill can your Jiachen cover?"

Lin Yuan turned toward the testing grounds below the bunker. The three Black Iron units stood there: Unit One straight and upright, Unit Two with its muzzle slightly lowered, Unit Three still slowly correcting its center of gravity.

"That's why the exercises must continue. Today was the first time. It won't be the last."

Ma Chongshan withdrew his hand from the parapet and wiped the concrete dust on his trouser leg.

"Director Lin, your Black Iron Squad is still far from combat-ready."

He walked toward the bunker stairway.

"But it's closer than I expected. The Ground Forces' requisition for eight units will be on your desk tomorrow."