 After 1919, two 8 cm/40 3rd Year Type naval gun were added for anti-aircraft defense abeam of the fourth funnel, replacing two of the 12-pounders in "Hirado" and three of the 12-pounders in "Yahagi" and "Chikuma".Three ships were budgeted for and completed under the 1907 Naval Expansion Program, one each from the Sasebo Naval Arsenal, Mitsubishi, Nagasaki and Kawasaki Shipbuilding, Kobe.All ships of the class served in World War I.