The plan included four armored cruisers and four battleships, all of which had to be ordered from foreign shipyards as Japan lacked the capability to build them itself.

[2] Unlike most of their contemporaries, which were designed for commerce raiding or to defend colonies and trade routes, the Izumo class was intended as fleet scouts and to be employed in the battleline.

[3] Construction of the Izumo-class ships was awarded to the British shipbuilder Armstrong Whitworth of Elswick, the same shipyard that had built the earlier two Asama-class armored cruisers of the "Six-Six Fleet".

They carried up to 1,527 long tons (1,551 t) of coal[9] and could steam for 7,000 nautical miles (13,000 km; 8,100 mi) at a speed of 10 knots (19 km/h; 12 mph).

[7] The main armament for all of the "Six-Six Fleet" armored cruisers was four Armstrong Whitworth-built 45-caliber eight-inch (203 mm) guns in twin-gun turrets fore and aft of the superstructure.

The eight-inch gun fired 250-pound (113.5 kg) armor-piercing (AP) projectiles at a muzzle velocity of 2,500 feet per second (760 m/s) to a range of 20,000 yards (18,000 m).

[11] The secondary armament consisted of fourteen Elswick Ordnance Company "Pattern Z" quick-firing (QF), 40-caliber, six-inch (152 mm) guns.

[21] In April 1904, the division was tasked to contain the Russian armored cruisers based at Vladivostok, but failed to do so until 13 August when the latter tried to rendezvous with the ships that attempted to breakout from Port Arthur.

Kamimura left Rurik to the tender ministrations of his reinforcements and pursued the two remaining Russian ships for a time before breaking off pursuit prematurely based on an incorrect report that Izumo had expended most of her ammunition.

Iwate, in contrast, was hit far fewer times, but one of them started a major ammunition fire that killed or wounded dozens of men.

[22] After the battle, the sisters were refitted and assigned to different units, escorting troop convoys to northern Korea, providing cover while a minefield was laid off Vladivostok, and blockading the Tsugaru Strait until the Russian ships from the Baltic Fleet approached Japan in mid-1905.

Izumo and Iwate had rejoined the 2nd Division in anticipation of this battle and Kamimura's ships confirmed the initial spotting later that morning before joining Tōgō's battleships.

After a failed torpedo attack was repulsed by Iwate and several other cruisers around the same time, the Russian battleship Knyaz Suvorov suddenly appeared out of the mist at 15:35 at short range.

After about half an hour, Admiral Ushakov had been heavily damaged to bear and her commander ordered his crew to abandon ship and the scuttling charges detonated.

[27] Izumo was ordered to patrol the west coast of Mexico to safeguard Japanese interests and nationals during the Mexican Revolution[28] and was still there when Japan declared war on the German Empire on 23 August 1914.

She was then tasked to search for German commerce raiders and protect Allied shipping off the western coasts of North and Central America.

[18] Iwate played a minor role in the war, participating in the Battle of Tsingtao[30] before sailing to the South Sea Islands to search for German commerce raiders.

[31] The ship began the first of her many training cruises for naval cadets of the Imperial Japanese Navy Academy in 1916, a task that would last until the end of 1939.

[33] The new boilers produced less steam which limited engine power to 7,000 ihp (5,200 kW) and reduced their top speed to 16 knots (30 km/h; 18 mph).

[18] During the Second Sino-Japanese War, the ship participated in the Battle of Shanghai in mid-1937 during which she provided naval gunfire support to Japanese troops ashore.

[18][36] On 31 December, the cruiser struck a mine in Lingayen Gulf while supporting Japanese forces during the Philippines Campaign.

When firing at surface targets, the Type 89 gun had a range of 16,100 yards (14,700 m); they had a maximum ceiling of 30,970 feet (9,440 m) at an elevation of +90 degrees.