The Yamato battleship: Imperial Japan's ultimate weapon and its dramatic demise

During the early 1930s, Japanese naval planners became increasingly concerned about the growing threat posed by the United States Pacific Fleet.

In response, the Naval General Staff proposed a new class of battleships capable of overwhelming American capital ships through sheer firepower and durability.

The result was the Yamato-class design. Naval architect Kikuo Fujimoto oversaw the initial plans, and naval engineer Captain Keiji Fukuda directed the project through its final stages.

Construction began on 4 November 1937 at the Kure Naval Arsenal, one of Japan’s most advanced shipyards. 

To make space for the vast scale of the vessel, engineers expanded existing facilities and reinforced drydocks.

The keel alone stretched further than any battleship previously built, and the hull required thousands of tonnes of high-tensile steel.

Skilled labourers, many of whom had worked on previous warships, carried out the work, which involved riveting and welding under tight military supervision.

The ship's propulsion system required four massive steam turbines connected to three propeller shafts, which generated a combined 150,000 shaft horsepower. 

Yamato launched on 8 August 1940 and officially entered service on 16 December 1941, only nine days after the attack on Pearl Harbor.

Though operational, the ship required additional fitting-out and testing before being fully combat ready.

For several months, it operated in home waters, during which crews were trained and procedures were improved.

The Imperial Japanese Navy had high expectations for the vessel, expecting it to play an important role in any large-scale surface engagement. 

At 263 metres in length and with a beam of 38.9 metres, Yamato was the largest battleship ever constructed.

Fully loaded, it displaced approximately 72,800 tonnes. Armour protection extended across the length of the ship, with a belt thickness of up to 410 millimetres and deck armour up to 200 millimetres.

This level of protection exceeded anything deployed by other navies at the time. 

The ship's main armament consisted of nine 460-millimetre (18.1-inch) guns housed in three triple turrets. Each gun could fire a 1.5-tonne shell over 40 kilometres.

Secondary weapons included twelve 155-millimetre guns, twelve 127-millimetre dual-purpose guns, and dozens of 25-millimetre anti-aircraft weapons.

Additional AA mounts were added during the war, which increased the total number of 25-millimetre guns to over 150 by 1945. 

Below deck, the ship contained advanced fire control systems, reinforced magazines, and many separate sections.

At full capacity, the ship carried over 2,700 personnel. The sheer size of the vessel made it slower to move than cruisers or carriers, and the designers chose to focus on durability and firepower rather than trying to improve the ship’s speed or manoeuvrability. 

To maintain a strategic edge, Japanese authorities imposed strict secrecy on every aspect of Yamato’s construction.

Workers at the Kure Naval Arsenal signed non-disclosure agreements and operated under constant watch by military police.

The site itself became heavily restricted, with security personnel who monitored movements and checked communications.

Construction took place in a covered drydock, which hid the ship from aerial scouting and limited visibility from nearby vantage points. 

Information about the ship’s specifications stayed tightly controlled and official documents avoided mentioning Yamato by name, instead using coded designations such as “Battleship No. 1.”

Public references to its size, speed, or details were forbidden, and officers aboard the ship followed orders to speak in vague terms during shore visits or correspondence. 

Japanese propaganda, which celebrated naval victories in the early stages of the war, made no mention of Yamato until much later.

Even after its official entry into service, the ship operated under radio silence when at sea, and fleet movements involving Yamato used deception measures to confuse Allied intelligence.

These efforts delayed Allied awareness of the battleship’s full details until late in the war, although scouting photos eventually revealed some of its characteristics. 

By 1945, Japan’s naval situation had deteriorated significantly. American submarine campaigns had crippled shipping lanes, and repeated carrier battles had destroyed much of the Imperial Navy’s striking power.

After the Battle of Leyte Gulf in October 1944, where Yamato fired its main guns in combat for the first time, remaining Japanese naval forces retreated to home waters.

Supplies dwindled, fuel reserves ran low, and strategic options narrowed. 

In April 1945, as American forces approached Okinawa, Japanese commanders approved Operation Ten-Go, a desperate attempt to disrupt the invasion.

The plan called for Yamato and a small escort group to sail south without air cover, engage the Allied fleet, and then beach the battleship on Okinawa’s shore to serve as a fixed gun platform.

The mission offered little chance of survival. Fuel limitations ensured the ship could not return to Japan, and planners accepted the vessel’s likely destruction. 

Yamato departed Tokuyama on 6 April 1945, escorted by one light cruiser and eight destroyers, but American codebreakers had already intercepted messages detailing the mission.

On 7 April, waves of carrier-based aircraft from Task Force 58 launched a massive assault.

Over 300 bombers and torpedo planes attacked the task force in repeated waves. 

Despite heavy anti-aircraft fire and evasive moves, Yamato absorbed numerous hits.

Bombs penetrated the deck, torpedoes ruptured the hull, and internal fires disabled pumps and power systems.

A massive explosion in the magazine at 2:23 pm broke the ship apart, sending it to the bottom with over 3,000 tonnes of ammunition still on board.

Out of a crew of roughly 3,300, fewer than 280 survived. Most of the escort vessels also sank or sustained heavy damage. 

Yamato’s loss showed the failure of the battleship doctrine in modern naval warfare and was among the last major naval actions of Imperial Japan.

Built to dominate the seas through size and firepower, Yamato never fulfilled its intended purpose.

Its final voyage instead became an act of sacrifice, ordered in desperation and remembered today as a final chapter to Japan’s maritime ambitions during the Second World War.