Iron Coffin

"Every time they underestimate East Asia, Ma Chongshan's chair moves another 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 Ground, Northern 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 dents left by seventy-six-millimeter autocannon shells during its first battle still marred its chest armor, unpolished. Units Two and Three had fresher paint jobs, with neatly edged dark-gray Ceramic Steel external plates and sealing strips at their joints that had yet to gather dust.

Han Zheng stood beneath Unit One's feet and looked up at the pilots of the other two machines climbing their boarding ladders.

Unit Two's pilot was Tian Mu, twenty-eight years old, 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 an MS before being transferred to the 811 Institute. His arms were as thick as calves, and he climbed the boarding ladder with the same practiced ease as scaling a tank's side skirt.

Unit Three's pilot was Liu An, twenty-five years old, a corporal from the same regiment. His record listed him as an armored communications soldier, but during exercises he had filled in twice as a gunner after the vehicle commander was injured, achieving the regiment's third-best annual score. He was half a head shorter than Han Zheng, but his palms were just as broad.

"Tian Mu, have you set the comms frequency?" Han Zheng shouted from the ground.

Tian Mu's voice came from Unit Two's cockpit, muffled as if 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 on the right. Can its position be changed?"

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

"Then I'll put up with it."

"If you can't, don't look at it. Listen instead. Jiachen will repeat key instructions aloud."

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

The observation area was set atop a concrete bunker on the eastern side of the testing ground, with a clear view of the entire northern open area. Ma Chongshan sat in a folding chair, with his adjutant and two staff officers beside him. Sheng Lan monitored the biometric data in the control room on the bunker's lower level.

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 by three units using interlocking fire. The simulated enemy consists of six ZAFT Ginn-type MS units. Jiachen will generate battlefield data in real time and project it onto moving targets in the exercise area."

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

"Live ammunition?"

"Low-charge training rounds. Their detonation signature matches combat rounds, but their lethal radius is reduced to within safe limits. Jiachen's sensor array will determine target destruction."

"Begin."

Lin Yuan pressed the communications key.

"Han Zheng, begin."

The plasma auxiliary drives of all three Black Iron units started at once. Their hum spread across the apron, making the water in the cups on the folding table atop the bunker ripple with fine tremors.

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 began walking was entirely different from the Short Sword's light, gliding steps. Their heavy feet slammed against the concrete, every step sending a faint tremor through the ground. The weight of their sixty-millimeter Ceramic Steel external plates made their joint actuators emit a constant sound of strain.

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 area, six moving targets activated at once, maneuvering at high speed according to the movement characteristics 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 simultaneously.

"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. It took him nearly two seconds to stabilize the muzzle over the target sector, and by the time he fired his first shot, the target had already left the optimal hit window.

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

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

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

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

Hit. A red confirmation light lit up on the target's surface sensor.

But a problem arose on the other side.

The two targets on Liu An's right flank chose high-speed crossing maneuvers, their trajectories repeatedly intersecting inside Unit Three's firing arc. Liu An fired twice and missed both shots. When he fired the third, the Bombard Gun's recoil threw the machine's right side off balance. Unit Three's right foot slipped past its footing line, and the entire machine tilted fifteen degrees to the right.

Ma Chongshan's chief staff officer spoke up.

"The formation's broken."

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

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

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

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

Liu An's voice was muted.

"Understood."

Unit Three stopped its tracking fire and braced the Bombard Gun at a fixed angle. The strain from its joint actuators eased. The two targets tried to circle in from the right and move behind the formation, but the instant they entered Unit Three's firing arc, they were forced to alter course and could never complete their encirclement.

Han Zheng used that opening to turn around. Unit One's Bombard Gun fired two consecutive rounds across the movement paths of the frontal targets, and two confirmation lights turned red at the same time.

Tian Mu followed up and took out the second target on the left flank.

The remaining two targets on the right circled three times outside Liu An's blocking sector, never finding an angle to break into the core. In the end, Han Zheng adjusted the formation. The three Black Iron units closed their spacing to form a dense wall of fire, and a six-round volley covered the targets' final movement path.

All six red lights came on.

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

Ma Chongshan rose from his chair, not out of excitement. He walked to the bunker's edge, rested a hand on the parapet, and looked down at the three Black Iron units standing below.

Unit One stood perfectly still. Unit Two's muzzle drooped slightly; Tian Mu was probably wiping sweat in the cockpit. Unit Three remained tilted 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. He was a communications soldier and temporary vehicle commander."

"No wonder he can't keep his footing. Tank crews are used to using the chassis's center of gravity to offset recoil. An MS's center of gravity is above the waist. He used a tank crewman's instincts to absorb the Bombard Gun's impact and overcompensated in the opposite direction."

Lin Yuan said nothing.

Ma Chongshan turned around.

"I understand your concept of formation fire coverage. You aren't pursuing individual accuracy. You overlap the firing arcs of three machines to create a blockade zone and force enemy units into a preset kill zone. It's a good idea."

He held up three fingers.

"Three problems. First, today's targets were set according to Ginn-type movement parameters, with a maximum speed of two hundred kilometers per hour. If you replace them with ZAFT commander units that move twice as fast, will 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, your ammunition consumption. You fired twenty-two rounds in four and a half minutes against six targets. That's an average of 3.7 rounds per target. In combat, each machine carries forty rounds, while a squad has one hundred and twenty. At this rate, your ammunition will be nearly exhausted after two waves of enemies. How will logistics keep up?"

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

"A resupply plan is already scheduled. Fang Heping has designed a quick-release ammunition feed box. Estimated replacement time in the field is ninety seconds."

"Ninety seconds." Ma Chongshan rolled the number over in his mind. "In battle, ninety seconds is enough time for the other side to make a full round trip."

"That's why they need positional support," Lin Yuan replied. "The Black Iron squad was not designed for independent maneuvering. It is meant to operate alongside defensive lines. Advance to preset positions, establish fire coverage zones, and wear down enemy manpower."

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 tank crewmen. Against six targets, Unit Three nearly fell over on its own. The people sent into battle after mass production will have even more varied backgrounds and uneven abilities. How great a gap in pilot skill can your Jiachen cover?"

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

"That is why the exercises must continue. Today was the first time, but it will not be the last."

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

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

He headed for the bunker stairway.

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