Laid down at the Yokosuka Naval Arsenal on 15 May 1905, launched on 15 November 1906, completed and commissioned on 25 March 1910, decommissioned In 1922, stricken on 20 September 1923 and as a result of the Washington Naval Treaty sunk while used as a target ship by the battleships Mutsu and Nagato off the southern end of the Boso Peninsila near the entrance of the Tokyo Bay on 7 September 1924.
Of the Satsuma-class consisting of the Satsuma and the Aki ordered under the 1904 War Naval Supplementary Program when Japan was in war with Russia (8 February 1904-5 September 1905). Preceded by the Katori-class and succeeded by the Kwawachi-class.
Displacement 19.683 tons/19.372 long tons and as dimensions 146,9 (over all) x 25,5 x 8,4 (standard) or 482 x 83.6 x 27.6 feet. Crew numbered between 800-940 men.
Fitted out with a pair pf vertical triple expansion steam engines with 20 oil fuel-coal fired Miyabara water tube boilers delivering totally 17.300 (design)-18.507 (sea trials) ihp and with one screw allowing a speed of 18,25 (design)-18,95 (sea trials) knots. With a speed of 10 knots was her range 9.100 nautical miles.
The armour consisted of a 10,2-22,9cm/4-9” thick Krupp cemented belt, 5,1-7,6cm/2-3” thick deck with the gun turrets, casemates and conning tower protected by respectively 17,8-22,9cm/7-9”, 15,2cm/6” and 15,2cm/6”. According to the preliminary designs was the intention this class with 12-30,5cm/12” guns but lacking sufficient numbers of guns in Japan and reducing the building costs was the armament radically changed. It consisted of 2x2-30,5cm/12” 45cal 41st Year Type guns, 6x2-25,4cm/10” cal 45 type 41 guns, 12x1-11,9cm/4.7”40 cal quick firing guns 8x1-7,6cm/3” 12 pd (4-40 cal, 4-28c al) guns and 5 submerged45,7cm/18” torpedo tubes (stern 1, broadsides each 2).
