Satsuma-class battleship

Postcard of Satsuma at anchor
Class overview
Name:	Satsuma class
Operators:	Imperial Japanese Navy
Preceded by:	Katori class
Succeeded by:	Kawachi class
Subclasses:	Aki
Built:	1905–11
In commission:	1909–22
Completed:	2
Scrapped:	2
General characteristics
Type:	Semi-dreadnought battleship
Displacement:	19,372–20,100 long tons (19,683–20,423 t)
Length:	482–492 ft (146.9–150.0 m)
Beam:	83.5–83.6 ft (25.5–25.5 m)
Draft:	27.5 ft (8.4 m)
Installed power:	17,300 ihp (12,900 kW) 20 Miyabara water-tube boilers (Satsuma) 24,000 shp (18,000 kW) 15 Miyabara boilers (Aki)
Propulsion:	2 shafts, 2 Vertical triple-expansion steam engines (Satsuma) 2 shafts, 2 steam turbine sets (Aki)
Speed:	18–20 knots (33–37 km/h; 21–23 mph)
Range:	9,100 nmi (16,900 km; 10,500 mi) at 10 knots (19 km/h; 12 mph)
Complement:	800–940
Armament:	2 × twin 12 in (305 mm) guns 6 × twin 10 in (254 mm) guns 8 × single 6 in (152 mm) guns (Aki) 12 × single 4.7 in (119 mm) guns (Satsuma) 8 or 12 × single 3 in (76 mm) guns 5 × 18-inch (457 mm) torpedo tubes
Armor:	Waterline belt: 4–9 in (102–229 mm) Deck: 2–3 in (51–76 mm) Gun turrets: 7–9.5 in (178–241 mm) Conning tower: 6 in (152 mm) Casemates: 6 in (152 mm)

The Satsuma class (薩摩型戦艦, Satsuma-gata senkan^?) was a pair of semi-dreadnought battleships built for the Imperial Japanese Navy (IJN) in the first decade of the 20th century. They were the first battleships to be built in Japan and marked a transitional stage between the pre-dreadnought and true dreadnought designs. They saw no combat during World War I, although Satsuma led a squadron that occupied several German colonies in the Pacific Ocean in 1914. Both ships were disarmed and expended as targets in 1922–24 in accordance with the terms of the Washington Naval Treaty of 1922.

The Satsuma class was ordered in late 1904 under the 1904 War Naval Supplementary Program during the Russo-Japanese War. Unlike the previous Katori-class pre-dreadnought battleships, they were the first battleships ordered from Japanese shipyards, although the first ship in the class, Satsuma, used many imported components.

They were originally intended to mount a dozen 12-inch (305 mm) gun in four twin and four single-gun turrets, but the combination of a shortage of Japanese-built 12-inch guns and their additional expense caused the ships to be redesigned to carry four 12-inch and twelve 10-inch (254 mm) guns, all in twin-gun turrets. The intended armament of these ships, laid down before HMS Dreadnought, would have made them the first "all big-gun" battleships in the world had they been completed to their original design.