Japan Stunned When America Used 60mm Mortars to Shatter Banzai Charge

October 25th, 1942, Henderson Field, Guadal Canal. The First Battalion, 7th Marines and the 164th Infantry Regiment Dig into defensive positions as Lieutenant General Misaw Maryama’s second division masses in the darkness. In the weapons platoon, Marine mortar crews check their 60mm M2 mortars one final time.

 Tonight, Edgar Brandt’s revolutionary French design will face its ultimate test against 3,000 screaming Japanese soldiers in the largest bonsai charge of the Pacific War. The story begins not in the steaming jungles of Guadal Canal, but in the workshop of a French iron worker named Edgar William Brandt, born December 24th, 1880.

 Brandt started as a silvermith in Paris, crafting jewelry and decorative iron work. When World War I erupted in 1914, this artist turned weapons designer would create something that would change infantry warfare forever. Observing French soldiers struggling in the trenches, Brandt designed an aerodynamic mortar shell with opteration grooves, a concept so revolutionary that his 1925 patent remains essentially unchanged today.

 His 60 mm, 81 mm, and 120 mm mortars would be copied by armies worldwide. But it was his 60mm design that would capture American attention. During the late 1920s, the United States Army faced a critical gap in infantry firepower. Hand grenades could reach 75 yards. The 81 mm mortar could hit targets 3,000 yd away.

But between these weapons lay a deadly void where enemy forces could mass undetected. The army needed something portable enough for company commanders, yet powerful enough to break up enemy attacks. In 1938, the United States War Department purchased eight of Edgar Brandt’s French-built mortars, standardizing them as the mortar 60mm M1.

 But American engineers at Waterle Arsenal, the nation’s oldest continuously active arsenal, had different ideas. They revised the production drawings, adapting them for standard American threads, tubes, and plates. When these modifications were complete, the weapon was redesated the mortar 60mm M2. Waterfleet Arsenal, established during the War of 1812, became the engineering heart of America’s mortar revolution.

 The facility had been building big guns since 1889. But the M2 represented something different. This wasn’t just another artillery piece. This was a weapon designed to put devastating firepower directly into the hands of infantry company commanders. In January 1940, the first production contract for 1,500 mortars was issued to the Reed Machinery Company of York, Pennsylvania.

As war clouds gathered over Europe, demand exploded. Kennedy Vanson Engineering Company in Danville, Pennsylvania joined production, followed by the Firestone Tire and Rubber Company. By war’s end, these American manufacturers would produce over 60,000 M2 mortars. The weapon that emerged from these factories was deceptively simple yet brilliantly engineered.

 Weighing 42 lb total, it broke down into three components weighing 12 to 16 lb each. The revolutionary feature was Brandt’s fixed firing pin design. Mounted permanently in the base cap of the tube. When a mortar round was dropped down the barrel, it struck the firing pin automatically, creating the fastest rate of fire of any mortar in the world.

 A trained Marine mortar crew could maintain 18 rounds per minute sustained fire. But in desperate situations when Japanese bonsai charges threatened to overrun American positions, crews could achieve nearly 100 rounds per minute with 15 to 20 shells in the air before the first round impacted. The M2 fired three primary types of ammunition.

 The M49 A2 high explosive round weighed 3 lb and created a 17yd kill radius. The M83 illuminating round weighed 3 12 lb, generating 11,000 candle power for 25 seconds as it descended on a parachute. The M302 white phosphorus round, introduced late in the war, created deadly screening smoke while incinerating anything it touched.

 Each round contained an M5A1 ignition cartridge, essentially a 20 gauge shotgun shell filled with ballastite powder. When the round hit the fixed firing pin, this cartridge detonated, launching the projectile up to 1,815 m downrange. Marine rifle companies organized their mortar sections differently throughout the war.

Initially 16 Marines formed the mortar section as part of the weapons platoon with a sergeant section leader commanding three mortar squads led by corporals. In May 1944, the Marine Corps eliminated the weapons platoon, placing 20 Marines in the mortar section under direct company headquarters control. The squad organization was precise and efficient.

 The corporal squad leader carried the M4 sight when moving. The gunner carried the complete mortar. The assistant gunner carried aiming stakes. Three ammunition bearers carried rounds in M2 ammunition vests, each capable of holding multiple shells. This organizational change reflected hard-learned lessons from the Pacific fighting.

 Company commanders needed immediate responsive fire support that could keep pace with rapidly changing tactical situations. The M2 mortar, nicknamed the company commander hip pocket artillery, provided exactly that capability. on Guadal Canal. As Moryama’s forces prepared their October assault, American Marines had been fighting for nearly 3 months to hold Henderson Field.

 The airirstrip was critical to controlling the Solomon Islands, and both sides knew it. Japanese destroyers pounded the field nightly in runs dubbed the Tokyo Express. American aircraft struck back during daylight hours, but the ultimate decision would come down to infantry fighting infantry. The Japanese plan was audacious.

 Moryama would march his second division through the jungle to attack Henderson Field from the south while diversionary forces struck from other directions. The assault force included the 16th and 29th infantry regiments, veteran units that had fought across China and Southeast Asia. American defenders included the first battalion, 7th Marines under Lieutenant Colonel Lewis Puller, reinforced by elements of the 164th Infantry Regiment.

These units had been testing their M2 mortars in smaller engagements for weeks, learning how to integrate the weapons into defensive fire plans. At 0445 hours on October 26th, Maryama’s forces struck. 3,000 Japanese soldiers charged toward the American lines, screaming bonsai battle cries and firing rifles from the hip.

 They had fought Chinese armies armed with obsolete weapons. They had overrun British forces in Malaya, but they had never faced the concentrated firepower that American M2 mortars could deliver. Marine mortar crews had pre-registered their weapons on likely approach routes as Japanese forces masked in the darkness.

 Forward observers called for fire. The first rounds were M83 illumination shells bursting overhead and bathing the battlefield in harsh white light. Suddenly, 3,000 charging soldiers were silhouetted against the jungle. Perfect targets for the high explosive rounds that followed. The M2 mortars fired so rapidly that the sound merged into a continuous roar.

 100 rounds per minute from multiple mortars created a steel rain that no infantry formation could survive. Japanese soldiers who reached the barbed wire perimeter found themselves trapped in a kill zone where mortar fragments and machine gun fire converged with devastating effect. Marine forward observers directed the fire with surgical precision.

 When Japanese forces bunched up at wire obstacles, high explosive rounds landed directly among them. When they tried to flank American positions, illumination rounds exposed their movements. The M2’s high angle of fire meant shells could drop into ravines and defilated positions where Japanese soldiers sought cover.

 By dawn, the battlefield was littered with over 1,500 Japanese dead. American losses were approximately 60 killed. The bonsai charge, a tactic that had worked against Chinese and Southeast Asian armies, had been shattered by American firepower. Moryama’s second division was finished as an effective fighting force.

 But the M2 mortar story was just beginning. Across the Pacific, other American units were discovering the weapon’s unique capabilities in different tactical situations. On Okinawa, April 13th, 1945, Technical Sergeant Buford Anderson of the 381st Infantry, 96th Infantry Division, found himself facing a different kind of crisis.

 A powerful Japanese counterattack had struck his units flank at dawn. Anderson ordered his men to take cover in an ancient Okinowan tomb while he faced the assault alone. Armed only with a carbine, Anderson emptied one magazine at pointblank range into the charging attackers. When his ammunition ran out, he seized an unexloded Japanese mortar round and hurled it back among the enemy soldiers, killing several when it detonated.

 But Anderson wasn’t finished. Spotting a box of American M2 mortar shells, Anderson extracted the safety pins and began banging the bases on rocks to arm them manually. Then he proceeded to throw these live shells like grenades among the attacking Japanese force. The mortar rounds were light enough at three lbs each that a strong man could hurl them effectively in close combat.

 Anderson’s desperate improvisation worked. The armed mortar shells exploded among the Japanese attackers, killing 25 enemy soldiers and destroying several machine guns and knee mortars. Anderson’s single-handed defense saved his unit and earned him the Medal of Honor from President Harry Truman. This incident revealed another aspect of the M2’s design genius.

 Edgar Brandt had created a weapon system so simple and reliable that individual soldiers could adapt it to unexpected tactical situations. The rounds were light enough for hand throwing when necessary, yet powerful enough to stop determined infantry attacks. Marine Eugene Sledge discovered yet another tactical application during his service with Company K, Third Battalion, Fifth Marines, First Marine Division on Paleu and Okinawa.

 Sledge served as a 60mm mortar man, experiencing firsthand how the weapon could solve tactical problems that had stumped larger artillery units. At one position on Okinawa, an elongated ridge had held up marine infantry attacks for three days despite heavy artillery support. Traditional artillery shells were exploding in front of or behind the Japanese defenders who had found a narrow ravine that provided perfect protection from flat trajectory fire.

Sledge’s mortar section, led by an experienced sergeant named Bergen, analyzed the tactical problem differently. They reasoned that the Japanese must be sheltering in a gully running along the ridge crest. Artillery couldn’t reach them because of the high angle protection, but mortars could. Bergen registered three M2 mortars with overlapping fields of fire.

 One mortar fired from right to left along the ridge, another from left to right, and the third directly down the crest. This triangulated fire pattern meant Japanese soldiers had nowhere to hide in the ravine. When the mortar barrage lifted, Marine infantry advanced against the ridge without receiving a single shot. Bergen’s inspection of the target area revealed more than 50 freshly killed Japanese soldiers in the narrow ravine.

All casualties of 60 mm mortar fire. Artillery shells had missed them completely, but the M2’s high angle trajectory had dropped shells directly into their sheltered position. This tactical success illustrated why the M2 earned its nickname as hip pocket artillery. Company commanders could position mortar sections to solve specific tactical problems that larger weapons couldn’t address.

 The weapons portability meant it could be moved quickly to support changing tactical situations. Japanese military analysts were studying these American tactics with growing concern. Capture documents reveal their assessment of American mortar effectiveness in detailed tactical reports. Japanese officers noted that American infantry companies always used heavy bombardment before attacking, making their movements predictable.

 But they also recognized the devastating effectiveness of American mortar fire. A Japanese analysis from Guadal Canal stated that American army has a weak point in its great susceptibility to artillery and bombing attacks, but acknowledged that American mortar sections could lay down persistent checking fire that made Japanese counterattacks extremely costly.

Japanese forces learned to hide in caves and tunnels during bombardments, only emerging when American infantry began advancing. However, Japanese tactical doctrine emphasized aggressive infantry action over heavy weapons support. While Japanese army mortars were more numerous in kind and number than in any of the armies engaged in World War II, Japanese officers believed that the feudal warrior spirit of individual soldiers was more important than firepower coordination.

 This philosophical difference created a tactical mismatch. American infantry companies with M2 mortars could coordinate fires with mathematical precision, while Japanese forces relied primarily on courage and surprise. When courage met coordinated firepower, the results were predictably one-sided. Japanese forces did attempt to counter American mortar effectiveness with their own weapons.

 The type 8950mm grenade discharger, nicknamed the knee mortar by Americans, was issued extensively to Japanese infantry units. A single Japanese rifle company could field 12 of these weapons compared to three M2 mortars in an American company. But the Japanese knee mortar had significant limitations. It could only fire grenades 75 yards maximum range compared to the M2’s 1,815 m capability.

 Japanese crews had to get dangerously close to American positions to be effective, exposing them to rifle and machine gun fire. The M2’s longer range meant American mortar crews could position themselves safely behind friendly lines while still supporting forward units. Japanese knee mortar crews had no such luxury, operating in direct contact with enemy forces where survival rates were much lower.

 As the Pacific War continued, American production of M2 mortars reached incredible levels. In 1945 alone, the first 8 months saw 30,152 mortars produced, nearly equaling the previous 3 years combined. Firestone Tire and Rubber Company, Kennedy Vanson Corporation, and Reed Machinery Company operated around the clock to meet military demands.

 Waterfleet Arsenal continued refining the manufacturing process throughout the war. The facility employed over 9,000 workers at peak production, turning out not just mortars, but artillery pieces for every theater of operations. From 1940 to 1945, Waterfleet’s workers assembled 49,052 cannons at a total cost of $260 million. The M2 mortar represented more than just a weapon system.

 It embodied American industrial capacity translated into tactical advantage. Edgar Brandt’s original French design had been brilliant, but American engineers and manufacturers had transformed it into a mass-roduced weapon that could equip every infantry company in the United States military. This production surge had strategic implications beyond individual battles.

 Japanese forces found themselves facing not just better trained American troops, but troops equipped with superior weapons in overwhelming quantities. Every American rifle company had immediate fire support organic to the unit. Japanese companies had to rely on regiment or division level assets that might not be available when needed.

 The tactical flexibility this provided was revolutionary. American company commanders could call for immediate mortar fire without requesting permission from higher headquarters. They could adjust fire missions in real time based on changing battlefield conditions. They could coordinate multiple fire missions simultaneously to support complex tactical maneuvers.

 Japanese commanders operating under a more rigid command structure couldn’t match this responsiveness. By the time Japanese officers could coordinate fire support, American units had already moved to new positions or completed their tactical objectives. This technological and tactical superiority became increasingly apparent as American forces advanced closer to Japan itself.

 On Euoima, February to March 1945, the Japanese had constructed the most elaborate defensive system in the Pacific War. 18 km of tunnels connected bunkers, artillery positions, and command centers across the volcanic island. Lieutenant General Tadamaki Korabayi commanded 21,000 Japanese troops armed with 320 mm spigot mortars, numerous machine guns, and carefully sighted artillery pieces.

Every square meter of Eoima was covered by pre-registered Japanese fire. The defenses were so strong that American intelligence estimated casualties could reach 75%. Yet, American forces, including 70,000 Marines equipped with M2 mortars, successfully captured the island in 36 days.

 The M2’s ability to drop shells into Japanese cave positions and reverse slope defenses proved crucial to the victory. While larger artillery often couldn’t reach Doug in Japanese positions, 60mm mortars could deliver precise fires anywhere on the battlefield. The cost was tremendous. American forces suffered 24,053 casualties with 6,140 Marines killed, but Japanese casualties were even higher with virtually the entire garrison eliminated.

 The M2 mortar’s contribution to this victory validated Edgar Brandt’s original design concepts under the most extreme combat conditions. As the war neared its end, American military leaders were already planning for future conflicts. The M2 had proven its worth in jungle fighting, amphibious assaults, urban combat, and defensive operations, but technology was advancing rapidly, and newer designs were already in development.

 The M2 would continue serving American forces through the Korean War and Vietnam War, finally being replaced by the M224 lightweight company mortar system in the 1970s. But its impact on military tactics and American industrial capacity had already secured its place in history. Edgar Brandt’s design revolution had achieved something remarkable.

 A French artist turned weapons designer had created a mortar system that gave individual infantry companies the firepower of artillery units. American engineers had refined and mass produced this design to equip the largest military force in history. The result was a weapon that helped American infantry dominate battlefields from Guadal Canal to Okinawa.

 The M2 mortar story reveals how technological innovation, industrial capacity, and tactical flexibility combined to create battlefield superiority. Japanese forces, despite their courage and determination, couldn’t match American units that possessed immediate, responsive fire support at the company level.

 When technical sergeant Buford Anderson threw armed mortar shells at attacking Japanese soldiers, he was using Edgar Brandt’s ammunition design in a way the French engineer never imagined. When Eugene Sledge’s mortar section eliminated 50 Japanese soldiers in a ravine that artillery couldn’t reach, they were applying tactical principles that revolutionized infantry warfare.

 When Marine mortar crews fired 100 rounds per minute to shatter bonsai charges at Guadal Canal, they were demonstrating how superior technology and training could defeat traditional military tactics. The screaming Japanese soldiers who charged Henderson Field that October night in 1942 faced not just American Marines, but the concentrated firepower of 60,000 mass produced mortars backed by the world’s most advanced industrial system.

 The fixed firing pin that made such rapid fire possible represented more than just clever engineering. It embodied American approaches to warfare that emphasized technological superiority, coordinated fires, and overwhelming material advantage. Japanese forces fighting with courage and determination discovered that bravery alone couldn’t overcome enemies equipped with hip pocket artillery that delivered 100 rounds per minute of precision destruction.

 From Edgar Brandt’s Paris workshop to Waterle Arsenal’s production lines to the volcanic beaches of Ewima, the M2 mortar connected industrial innovation with battlefield victory. American company commanders who called their mortars hip pocket artillery weren’t just describing a weapon. They were describing a tactical revolution that transformed infantry warfare forever.

 The Japanese soldiers who faced these weapons at Guadal Canal, Saipan, Ewoima, and Okinawa fought with traditional tactics against an enemy that had fundamentally changed the nature of infantry combat. When the last M2 mortar round exploded on August 15th, 1945, it marked not just the end of World War II, but the end of an era when courage and determination alone could decide battles between infantry forces.

 Edgar Brandt’s revolutionary design had given American infantry companies the power to shatter bonsai charges, eliminate dug in positions, and coordinate fires with mathematical precision. The hip pocket artillery that stunned Japanese forces across the Pacific represented more than just superior weapons. It represented the triumph of industrial democracy over military authoritarianism, of technological innovation over traditional tactics, of coordinated firepower over individual heroism.

 In 60mm mortars firing 100 rounds per minute, Japanese military leaders glimpsed the future of warfare and realized their empire faced an enemy that had fundamentally changed the rules of battle itself.