18th Infantry Regiment ( Imperial Japanese Army ) The was an infantry regiment in the Imperial Japanese Army ( IJA ) . Its call sign and unit code was . The unit was formed in 1884 and based in the city of Toyohashi as a branch of the Nagoya Garrison . Throughout its history , the majority of its soldiers came from the Mikawa region , or eastern Aichi prefecture . The regiment first deployed for the First Sino - Japanese War in 1894 . In 1904 , it deployed again for the Russo - Japanese War where it fought in several major battles . Between 1928 and 1936 , the regiment was deployed to China where it engaged in two military operations in China , though it spent most of the time on garrison and occupation duty . With the start of the Second Sino - Japanese War in the summer of 1937 , the regiment participated in the Battle of Shanghai and then participated in the major campaigns of central China . In 1944 , the 18th Regiment was sent to the Pacific theater as part of the 29th Division . On the way to Saipan , the transport ship that was carrying the regiment , the " Sakito Maru " , was torpedoed and sunk . Over half the regiment drowned , but survivors were rescued and delivered to Saipan . Some stragglers had to be left behind , but the majority of the regiment was sent to Guam and prepared to repel the American invasion . Members of the 18th Regiment participated in both the Battle of Saipan and the Battle of Guam . In both battles , nearly all soldiers of the 18th Regiment were killed in action . A few soldiers survived the massed banzai charge s and attempted to evade capture by hiding in the jungles , but as an organization the regiment became defunct and the ranks were not replenished . After the battle on Saipan , one officer of the regiment , Captain Sakae Ōba , distinguished himself when he took command of some soldiers and assumed responsibility for the civilians who had survived the battle . Ōba and his men surrendered in December 1945 , three months after the official end of World War II . Early history . The three battalions of the 18th Infantry Regiment were established in Nagoya , Japan , and granted their colors on 15 August 1884 . By 1886 the regiment had transferred its headquarters to Toyohashi city , and thereafter the majority of its recruits came from that city and the surrounding Mikawa region of eastern Aichi Prefecture . In May 1888 , the IJA 3rd Division was organized and the 18th Infantry Regiment was placed in its command . The regiment deployed for the first time in 1894 to participate in the First Sino - Japanese War ( 1894 – 1895 ) . In 1904 , the regiment deployed again for the Russo - Japanese War . The regiment saw combat at the Battles of Nanshan , Te - Li - Ssu , Tashihchiao , Shaho , Panlongshan , and other places . In 1907 the regiment was transferred from the 3rd Division to the IJA 15th Division . In 1925 , the 15th Division was disbanded by order of War Minister Ugaki Kazushige , and the regiment was returned to the 3rd Division . In May 1928 , the regiment deployed for the Jinan Incident , and afterward served as the garrison for Tianjin , China . In February 1933 the regiment participated in Operation Nekka . As a result of this early clash between Chinese and Japanese forces , Inner Mongolia was placed in the Japanese controlled state of Manchukuo . In 1934 , the regiment was on garrison duty in Manchukuo . The regiment returned to Toyohashi , Japan in 1936 . Second Sino - Japanese War . With the outbreak of war following the Marco Polo Bridge Incident , the 18th Regiment was ordered to mobilize in August 1937 . The regiment landed and participated in the Battle of Shanghai , then continued on to assist with the Battle of Nanjing . In early December , the regiment crossed the Yangtze at a point about halfway between Shanghai and Nanjing , launching an attack from Jiangyin on the south bank to Jingjiang on the opposite bank . The regiment occupied the two towns until 9 March 1938 . Later in 1938 the regiment participated in the Hankou Operation as part of the larger Battle of Wuhan . In 1939 , it fought the Battle of the Xiang River , the First Battle of Changsha , as well as smaller actions in the area . In 1940 , the 18th Regiment participated in the Ichang Operation and the Han River Operation , both in Hubei Province . In July 1942 , command of the 18th Regiment was transferred from the 3rd Division to the IJA 29th Division . The regiment was then ordered to serve as the garrison force at Haicheng , at the time in Mukden Province , now part of Liaoning Province . By early 1944 , much of northern China was nominally secure , and many units were being transferred to various islands in the Pacific in order to support the strained and hyperextended line of defensive positions . By February 1944 , the 29th Division , which consisted of the 18th , the 38th , and the 50th Infantry Regiments , was ordered to mobilize and prepare for operations in the Pacific . Pacific Theatre . From Manchuria , the 18th Infantry Regiment and its sister regiments travelled to Korea , where they embarked on four transport vessels at Pusan . The convoy was escorted by three " Yugumo " - class destroyers of Destroyer Division 31 : , , and , and were first sent to the Japanese - held island of Saipan . On 29 February 1944 the transport ship carrying the regiment , the " Sakito Maru " , was hit by a torpedo fired from the , an American submarine , just northeast of Saipan . The transport sunk , taking with it 2 , 200 of the 3 , 500 men on board , which included the regimental commander , Colonel Monma Kentaro . Also lost on the transport were several tanks and most of the regiment ' s equipment . The convoy ' s three escort destroyers dropped depth charge s , sank the " Trout " , and then rescued the survivors of the sunken transport . About 1 , 800 troops of the regiment were delivered to Saipan . Saipan . After re - organization , two battalions of the under - equipped 18th Regiment was transported to Guam in May 1944 ; however , about 600 troops of the 1st Battlion had to be left behind on Saipan . These troops , under Captain Masao Kubo , joined the island ' s garrison , though nearly all would be killed during the Battle of Saipan in June and July 1944 . In the aftermath of the battle , Capt . Sakae Ōba distinguished himself by taking command of a number of soldiers and sailors who had survived the battle , as well as Japanese civilians who looked to him for guidance and protection . The group numbered about 300 , and took shelter in caves or small villages in the jungle . They evaded capture by the U . S . Marines that were hunting for them , conducted harassment raids , and survived until they finally agreed to surrender in 1 December 1945 . Guam . In March 1944 , the 29th Division commander , Lieutenant General Takeshi Takashina , landed on Guam and assumed overall command of all military units for the island ' s defense . In preparation for the imminent invasion of Guam by Allied forces , the main body of the 18th Regiment was situated on a mountain , with each company deployed to cover possible landing points in support of the island ' s defensive strategy . On 21 July 1944 the American landing operation commenced . Despite fierce resistance , United States Army and Marine forces gained two beachhead s by nightfall , straddling the Orote Peninsula on the west coast of the island , while the defenders either counterattacked or continued to fire on American positions with machine guns , artillery , and mortars . On 24 July , the command headquarters of the Japanese forces on Guam received word from Tokyo to " Defend Guam at all costs " . General Takashina devised a plan of attack to dislodge the 3rd Marine Division , which occupied the high ground at Asan , north of the Orote Peninsula . Takashina ' s attack would be coordinated with a breakout attempt of Japanese forces trapped on the peninsula . The 18th Regiment , which had been reorganized into three battalions , was to be one of the main units to assault the American position . Two battalions would attack the 21st Marine Regiment and the other battalion was to attack the flank of the 9th Marines . The objective was to exploit an 800 - yard gap between the two regiments , break through the American lines , and attain the high ground . Other units would attack the Marines or head to the beaches with demolition charges to destroy any ammunition or supply caches left by American forces . On the night of 25 July , the colors of the 18th Infantry Regiment were ritually burned , by authorization of the division commander , in anticipation of the regiment ' s complete destruction . First Battalion . Just after midnight , the 1st Battalion , 18th Regiment , attacked the center of the 22nd Marines . Veterans of the battle later reported that while many of the Japanese soldiers carried rifles and their officers led with swords , some of the Japanese carried knives , pitchforks , or their bayonets mounted to long sticks and used as spears . Charging across open ground , they were hit by American artillery , mortars , and machine gun fire until they retreated into a mangrove swamp . Artillery continued to bombard the swamps , discouraging further attack from that approach . Second Battalion . The Japanese main attack was launched at about 0300 , 26 July . The assault of the 2nd Battalion , 18th Regiment , under Major Maruyama Chusa , struck the center of the 21st Marines , and was the scene of some of the most desperate hand - to - hand combat of the entire night . The battalion charged through machine gun and artillery fire in an effort to reach the Marines . In an effort to break through the lines , Maruyama ' s men fought their way into a draw that led down to the beach . The Marines had prepared for that possibility , and once in the draw the Japanese faced several Sherman tank s . Lacking any sort of anti - tank weaponry , the Japanese troops were unable to damage a single tank , and flowing over and past them , continued on down the draw . Those troops who were unable to reach the draw regrouped and charged another point in the Marine line and fought hand - to - hand until their numbers became depleted . Third Battalion . The 3rd Battalion of the 18th Regiment , led by Major Yukioka Setsuo , was able to exploit a gap between the lines of the 9th and the 21st Marines , and drove hard toward the Marines ' regimental Command Post ( CP ) near the beach . The Japanese came close to overrunning the CP , but Yukioka ' s attack was blunted by desperate fighting during the Marines ' counterattack supported by artillery and mortars . One element of the 3rd Battalion encountered and attacked the 3rd Marine Division Headquarters area . The Japanese were prevented from overruning the position only when every available Marine , including cooks , clerks , doctors , and some of the wounded , joined the fighting , before two companies of combat engineers arrived to support the defenders . The engineers counterattacked , and by dawn the Japanese troops were dead or scattered ; many fled up the Nidual River valley . The Engineers pursued , and over the course of the day reported witnessing many of the Japanese committing suicide by an unprecedented method : when a Japanese soldier had given up on escape , and capture seemed imminent , he pulled the pin of his grenade , placed it on top of his head , then held his helmet down over the grenade and waited for the inevitable . By the morning of 26 July , it was apparent that the attack to dislodge the American position had failed , as had the breakout attempt at Orote Peninsula . It was also apparent to General Takashina that victory at Guam would be impossible , due to enormous losses in personnel , leadership , weapons , and morale . Takashina decided that all remaining troops should escape to the interior of the island , in order to regroup , and carry on a guerrilla campaign to inflict as much damage as possible on the American forces . During the previous night ' s fighting , most of the men of the 18th Regiment had been killed in action , along with their commanding officer , Colonel Hikoshiro Ohashi . By the end of 26 July 1944 , the 18th Infantry Regiment had ceased to be a functioning unit . Memorialization . The main memorial for the 18th Infantry Regiment is located in Toyohashi City Park . There are also monuments on the islands of Saipan and Guam , paid for by the regimental veterans ' association .