The Imperial Japanese Navy had adopted the Kantai
Kessen naval strategy before World War 2 even broke out.
Based on the works of American naval historian Alfred Thayer Mahan, Japanese strategists
believed their country could emerge victorious in an ocean war by a single, decisive action
through the effective use of a strong battleship force that could out-gun and outfight the enemy.
To achieve the purpose of Kantai Kessen, the Japanese Navy aimed to create the largest guns
ever installed on a vessel. The result was the 46-centimeter 45 Type 94 naval rifle,
a wire-wound gun mounted in three 3-gun turrets.
This weapon was so massive that it had roughly the weight of an average destroyer vessel.
The mighty Yamato-class battleship was equipped with this formidable weapon,
and sailed in the Pacific for years. However, instead of boasting about the size of the gun,
the Japanese kept it hidden from the Allies until after the war had ended.
The Allies didn’t know it yet, but they were fighting against the largest guns ever made…
The Most Powerful Battleship In The Pacific
In the 1930s, Japan's government, controlled by the military branches, felt that it could
and should dominate all of East Asia through military force. Consequently, the Empire adopted
an ultra-nationalist and militant approach to significantly expand its already vast territory.
After withdrawing from the League of Nations in 1934, which was the first intergovernmental
organization established to maintain world peace, Japan renounced the treaty's clauses
and obligations. This was followed by its retreat from the Washington Naval Treaty,
which limited the power, size, and number of capital ships.
Recognizing that Japan would be unable to compete
with the output of the United States naval shipyards should war break out,
Imperial Navy planners began designing a new class of heavy battleships.
The result was the Yamato class of battleships,
named after an ancient Japanese province. With a weight of 70,000 tons, the Yamato class was
designed to engage multiple enemy battleships simultaneously and was specifically created to
counter the numerically superior US battleship fleet, Japan's main rival in the Pacific.
During construction, the Japanese Navy made great
efforts to ensure the ships were built in extreme secrecy to prevent American
intelligence officials from learning of their existence and specifications.
The keel of the Yamato, the lead ship of the class, was laid down in 1937 at the
Kure Naval Arsenal in a dockyard that had to be adapted to accommodate her enormous hull.
Launched on August 8, 1940, with Captain Miyazato Shutoku in command, the lead ship
was formally commissioned seven days after the infamous Pearl Harbor attack in December of 1941.
With a displacement of almost 72,000 tons and a maximum speed of 27 knots,
the Yamato class was the largest and most powerfully armed battleship ever
constructed. It was fitted with nine 46 centimeters, 18.1 inches,
Type 94 main guns, the largest ever mounted on a warship, and had a total crew of 2,800.
Type 94
The Type 94 naval rifle was a wire-wound gun. The complex gun's barrels were structured in
three separate stages. The barrels of this complex gun were structured in three stages.
First, a half-length tube was fitted over the first tube and shrunk onto it. The assembly
was then wire-wound, and two more tubes were shrunk over the entire length of the gun tubes.
Finally, an inner tube was inserted down the gun and expanded into place,
and this inner tube was rifled to finish the gun.
The manufacturing process was so expensive that war planners considered
it more practical to simply replace a worn-out system with a new one. However,
there is no record of either battleship armed with Type 94 cannons being returned during the war.
The shell hoists and powder rams were ingeniously designed but heavy. The
shells were stored in a vertical position, and a system of geared mechanical conveyors
was responsible for moving the huge and heavy rounds from the shell rooms.
Nevertheless, this mechanical advantage meant the conveyors were extremely slow to operate
and reload. Despite this, the 180 shells stored in the turret's rotating structure,
60 rounds per gun, were considered sufficient for surface engagement.
Massive
When the Type 94 guns were mounted, each of them weighed 2,510, roughly
the same tonnage as an average-sized destroyer of the World War 2 era.
In an effort to hide the weapon's actual size, the guns were designated as much smaller,
only 15.75 inches, and remained a close-guarded secret until after the end of the war.
The first of the 27 produced guns was completed in March of 1938 and was tested
at the Kamegakubi proving grounds. During trials, the blast at the Kamegakubi test
range was 100 pounds per square inch at a target 50 feet in front of the muzzle,
twice as high as that for the guns used on the earlier Nagato class.
Although Britain later designed the N3-class battleship fitted with 18-inch guns,
none were actually built, leaving no Allied naval guns to compare with the Type 94.
While closely matched by the American-made 16-inch Mark 7 at long ranges,
the 18.1-inch cannons used on the Yamato class battleship were the most powerful
guns ever installed on a vessel of its kind. Particularly in close-range engagements,
the penetration power of the Japanese weapon was unsurpassed.
According to some Japanese accounts, the Type 94's muzzle blast was said to have been
powerful enough to rip the clothes off personnel standing too close when the guns were fired.
Additionally, unlike most of the guns of other navies,
Type 94 could fire special anti-aircraft shells, referred to as Sanshiki, or “beehive,”
which combined shrapnel and incendiary anti-aircraft rounds against enemy vessels.
Guns In Anger
In the late 1930s, Imperial Japan planned for five Yamato-class battleships, but only two,
Yamato and Musashi, were ever completed,
while a third was converted into an aircraft carrier that sank even before entering combat.
The only time Yamato fired her Type 94 main guns at Allied surface targets was on October 25, 1944,
during the Battle of Samar as part of the larger Battle of Leyte Gulf.
While threatening to sink American troop transports,
the Japanese encountered a light escort carrier group of the US Navy's Task Force 77, Taffy 3.
After engaging with the enemy forces invading the strategically essential Philippines,
she fired the largest guns in the world and reportedly sank one carrier and three destroyers.
However, the Japanese in the area lost three heavy
cruisers and retreated rather than risking a climactic battle,
as the American air attacks convinced them they were engaging a powerful carrier fleet.
About a month later, Mushashi, the second of the Yamato class,
also fired her main guns for the first and only time.
During the Battle of the Sibuyan sea in October of 1944, the Yamato-class
Mushashi fired Sanshikidan rounds; however, during the firing process, one of the shells
reportedly detonated in the middle gun of Turret 1, possibly due to a bomb fragment in the barrel.
The accident wrecked the turret's elevating machinery.
That same month, on October 24, during the Battle for Leyte Gulf, Musashi was sunk by
almost 20 torpedoes and 17 bomb hits from American carrier-based aircraft. Now, only
the flagship Yamato's Type 94 guns remained as the only act of their kind within the Imperial Navy.
Turn Of The Tides
By 1945, the naval power balance in the Pacific Theater had decisively turned against the Empire,
and not even the largest guns in the world could save Japan. As the year progressed, the Imperial
fleet became depleted and severely hobbled by critical oil shortages in the home islands.
In a desperate attempt to slow the Allied advance,
Yamato was dispatched on a one-way mission to Okinawa, with direct orders to beach herself
and fight against the enemy until destroyed, as a last-ditch effort to protect the island.
However, insufficient air cover and fuel cursed the endeavor as a suicide mission.
After being spotted south of Kyushu by American submarines, Yamato was bombarded
with carrier-based bombers and torpedo bombers. On April 7, 1945, one of the greatest battleships
of its time was sunk in Japan's first major counteroffensive in the struggle for Okinawa.
Weighing 72,800 tons, the massive ship, her nine guns, and most of her crew were sunk,
disappearing Japan's only hope of destroying the Allied fleet off the coast of Okinawa.
In total, 27 Type 94 naval guns were produced by the Japanese Imperial Navy,
with 18 of those lost with the sinking of Yamato and Musashi. In accordance with the United States
Army's order of disarmament, two additional test guns were demolished, while the remaining seven
were found in various stages of completion on a beach north of the Kamegakubi test firing site.
The last two, Number 23 and Number 27, were taken to the Dahlgren Proving Grounds in Virginia,
United States, for testing, arriving in June 1946. Upon a thorough examination by
a United States Naval technical team, the Type 94 turrets were found to have nothing
in common with British Vickers designs and were, in fact, entirely original...
According to rumors, the guns and the slides that arrived later were cut up for scrap sometime in
the 1950s. To this day, the Type 94 naval gun remains the largest ever mounted on a warship.
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