Japanese Fast Battleship Design vs. the Royal Navy

Japanese Fast Battleship Design vs. the Royal Navy


Two men standing over the interior of an airplane's cockpit

Captain Sempill showing a Sparrowhawk fighter to Admiral Tōgō Heihachirō, 1921. Japan had great admiration and respect for the Royal Navy.

Battleships, as manifestations of national power and prestige, played crucial roles in the 20th-century naval warfare narratives. While several nations embarked on ambitious battleship construction programs, the designs adopted by Japan and the UK offer interesting contrasts rooted in their unique strategic goals, geographical challenges, and technological preferences.

The battleship became a defining symbol of naval power!


The signing of the Washington Naval Treaty, 1922.

The Washington Naval Treaty (1922)

After the devastation of World War I, major naval powers felt the pressing need to prevent an arms race in naval shipbuilding, which could potentially lead to another global conflict. The Washington Naval Conference, held between November 1921 and February 1922, sought to address this concern. The result was the Washington Naval Treaty, signed on February 6, 1922.

The treaty established tonnage ratios for capital ships among the signatories, with the U.S. and Britain each allowed 525,000 tons, Japan 315,000 tons, and France and Italy each 175,000 tons.The treaty also specified the age at which ships could be replaced. For instance, no capital ships could be replaced until they had been in service for 20 years. The U.S. and Britain agreed not to fortify their possessions in the western Pacific, while Japan promised the same for its eastern territories.


The battleship Nagato in the early 1920s.

Moreover, with major maritime nations like Japan and the United Kingdom investing heavily in their construction and deployment. However, distinct strategic imperatives, technological advancements, and geographical considerations led the two nations down divergent design paths.

1. Introduction:
Japan and the United Kingdom, while both island nations, faced disparate challenges in the early to mid-20th century. The expansionist aspirations of Japan in the Pacific, juxtaposed against Britain’s global maritime dominance and the need to protect a vast empire, had profound implications for their respective battleship designs.

2. Historical Context and Strategic Imperatives:


The Royal Navy‘s revolutionary HMS Dreadnought, launched in 1906, gave its name to the type.

The challenge posed by Germany’s Kaiserliche Marine, especially during World War I, drove the British toward the development of the Dreadnought and the Grand Fleet doctrine.

  • Royal Navy: Britain’s naval doctrine was influenced by the need to secure its extensive overseas colonies and trade routes, ward off continental threats, and maintain its reputation as the world’s premier naval power.

Fort St. George in Madras, India was founded in 1639.


A map of the British Empire in 1921 when it was at its height, just before the Anglo-Irish Treaty of 1921. (But 1921-1937 Ireland continued to have the same status as Canada, Newfoundland, the South African Union, Australia and New Zealand, that is to be part of the British Empire as a dominion).

  • Imperial Japanese Navy (IJN): Japan’s outlook was primarily regional. Having witnessed the benefits of a superior navy during the Russo-Japanese War, Japan sought to establish dominance in the Pacific, anticipating a climactic showdown, likely against the U.S. Essentially, The Imperial Japanese Navy (IJN) envisioned a “Decisive Battle” doctrine, predicated on delivering a catastrophic blow to an advancing enemy fleet.

Britannia Royal Naval College.

3. Design Differences:

Imperial Japanese Navy battlecruiser Haruna at Yokosuka, Japan.

  • Armor and Armament: The Royal Navy typically favored balanced designs with good armor, armament, and speed. However, Japanese battleship design, influenced by the “Decisive Battle” doctrine, often prioritized heavier firepower and speed at the expense of armor, resulting in fast battleships like the Kongo class and, later, the Yamato class with its massive 18.1-inch guns.
  • Speed and Range: Japanese designs often emphasized longer operational ranges and higher speeds to cater to the vastness of the Pacific. In contrast, Royal Navy battleships, while maintaining respectable speed, were not as consistently oriented toward extended operational ranges, given Britain’s network of worldwide naval bases.
  • Dual-Purpose Guns: While both navies acknowledged the increasing threat of aircraft by the interwar period, Japanese designs like the Yamato incorporated more advanced dual-purpose guns that could target both ships and aircraft. The Royal Navy was slower in integrating this technology, instead often relying on separate anti-aircraft batteries.

Let’s jump into the Royal Navy & Dual-Purpose Guns!


Left rear view of a Mark 37 5″/38 caliber mount. NOTE: No Fuze Setter.

The integration of dual-purpose (DP) guns in the Royal Navy, compared to some other navies, was a relatively slow process!

The Royal Navy, given its long-standing history and traditions, often held conservative views about naval warfare and the roles of various ship types. As a result, this conservatism sometimes led to a reluctance in adopting newer technologies, favoring tried-and-true methods. Before the true threat of air attack was fully understood, the Royal Navy believed that their existing anti-aircraft (AA) systems, primarily based on smaller caliber weapons like the 2-pounder “pom-pom”, were sufficient.


Gunners on HMCS Assiniboine fire their 2 pdr while escorting a troop convoy from Halifax to Britain, 10 July 1940.

During the inter-war period, the Royal Navy was primarily concerned with the naval threats posed by Germany and Japan. The focus was on big-gun engagements and not so much on the increasing threat from the air. The early stages of WWII, especially the devastation wrought by German air raids, changed this perception.

Dual-purpose guns required advanced fire control systems to be effective against both surface and air targets. Developing these systems to be both reliable and efficient presented technical challenges.


8-barrelled “Chicago piano” on HMS Rodney, viewed from below.

However, the experiences in the early years of World War II, such as the significant losses in the Mediterranean to air attacks, made the need for improved AA capabilities apparent. Thus, the navy started to integrate more dual-purpose guns into their ships as the war progressed, but the initial lag meant they were catching up to a threat that had already manifested.

Many Royal Navy ships, especially older ones, had limited space and weight allowances for modifications. Fitting dual-purpose guns, with their associated fire control systems, wasn’t always feasible without significant redesigns or compromises in other ship capabilities.

  • Torpedo Armament: A significant divergence was Japan’s frequent inclusion of torpedo armament on its capital ships, a reflection of its success in night-battle torpedo tactics. British battleships, on the other hand, did not incorporate torpedoes, viewing them as more suitable for smaller ships.
The Yamato-class Battleships Yamato and Musashi moored in Truk Lagoon, in 1943.

4. Technological Innovations and Constraints:
Britain’s global commitments necessitated a broad spectrum of ship types, which might have diluted the focus from fast battleships. Japan, driven by its regional objectives, invested heavily in technological innovations for battleship design.

5. Operational Outcomes:
Despite their design distinctions, battleships from both nations faced challenges in World War II. A testament to the changing nature of naval warfare. The Royal Navy’s battleships were crucial in various theaters. But Japanese battleships, while impressive on paper, often faced logistical challenges. In addition, were not always optimally deployed, with the Yamato, for instance, seeing limited combat before its ill-fated last mission.


Kongō following her first reconstruction.

In, conclusion, the disparate design trajectories of Japanese fast battleships and those of the Royal Navy reflect deeper strategic and geographical distinctions. While both nations produced iconic battleships, their effectiveness was as much a product of strategic deployment as design superiority. The shift toward aircraft carriers during and post-World War II further underscores that design alone cannot determine naval dominance.


  • Dull, Paul S. A Battle History of the Imperial Japanese Navy (1941-1945). Naval Institute Press, 1978.
  • Gordon, Andrew. The Rules of the Game: Jutland and British Naval Command. Naval Institute Press, 2012.
  • Jordan, John. Warships after Washington: The Development of the Five Major Fleets, 1922-1930. Naval Institute Press, 2011.
  • Tully, A.P. Battleship Musashi: The Making and Sinking of the World’s Biggest Battleship. Kojinsha, 2019.

Japanese Fast Battleship Design vs. the Royal Navy