1) At or near maximum elevation, the rate of fire slowed to 2 to 3 rounds per minute for most mounts.  The pusher hoists used for the "E" turrets could bring shells to the gunhouse at a maximum rate of four shells per minute.

2) When it came time for Furutaka and Kako to be rearmed in the 1930s, production difficulties held up deliveries of the 20 cm (8") 2 GÔ guns intended for these ships.  Rather than wait for these guns to be completed, the Japanese instead took 20 cm (7.9") 1 GÔ guns removed from Haguro and Ashigara, rebored and relined them to 20.3 cm (8"), and then installed them onto Furutaka and Kako.  I would assume that these guns would have been replaced with standard 20 cm (8") No. 2 weapons during any regunning operations during the war.

1) IS is my abbreviation for the incendiary shrapnel round (sankaidan) intended for AA use.  This was officially listed as a Common shell, but was actually an incendiary fragmentation round.

2) The propellant charge was in two bags.

3) Type 91 shells were all 6 / [infinity] crh with boat tail and two copper driving bands.  The diameter of the bourrelet was 7.96 in (20.218 cm).  These 20 cm (8") Type 91 shells were not true "APC" projectiles as they lacked a cap, having only a cap head and windshield.  Cap head and windshield together weighed 17 lbs. (7.7 kg).  There were true APC projectiles, designated as Type 91 Mod 1, but these were used only for armor penetration experiments and were not in service.

4) The Shômeidan B Illumination round had an effective range of 17,500 yards (16,000 m) and an illuminating power of 1.6 million candelas.  The maximum ballistic range was 24,900 yards (22,770 m).

5) In addition to the projectiles listed above, there were also Type 91 Exercise and Type 91 Timed Exercise shells.

6) According to "Japanese Cruisers of the Pacific War," the average maximum range for the 10-gun cruisers for daylight actions increased from about 16,840 yards (15,400 m) in 1924 to greater than 21,870 yards (20,000 m) by 1937 and the estimated hit projection increased from 3.0% at 21,870 yards (20,000 m) in 1930-34 to 6.0% in 1935-1940.  The actual percentage of hits achieved during the war was much lower than these figures, a not unusual experience.

   Takao (5):  Model E
   Maya (5):  Model E₁
   Furutaka (3):  Model E₂
   Mogami (5):  Modified E₂
   Tone (4):  Model E₃
   The Aoba class retained their (3) Model C mountings
   The Nachi and Myoko classes retained their (5) Model D mountings

1) When converted to the No. 2 weapons, the Type C and D mountings were modified to increase their maximum elevation to +40 degrees.  It is possible that Aoba was later modified to +50 degrees.

2) For the Mogami class, as these guns were longer than the 15.5 cm (6.1") guns they replaced, the guns of No. 2 turret could not depress below +12 degrees when trained on the centerline.  Otherwise, they would have struck No. 1 turret.

3) The "Modified E2" turrets used on the Mogami class had a larger diameter roller path to fit the triple 15.5 cm (6.1") barbette.  Taking this and Note 2 into account, it would appear to be a myth that these ships were designed with the potential for mounting 20.3 cm (8") guns in mind.

4) During modernization and replacement of the 20 cm (7.9") No. 1 with the 20 cm (8") No. 2, the Furutaka class was converted from six "A" single mounts to three "E2" twin mounts.

5) These mountings varied in detail from class to class and even within a class but many features were the same.  They were operated with very noisy electric motor driven oil hydraulic pumps located in the revolving structure.  Damage to rubber covered wiring by oil leaks was a common complaint.  Run out was by compressed air.  Elevation was by rack and pinion on the C, D and E₁ mountings and by hydraulic actuators on the other E types.  The Modified E₂ and E₃ mountings had 315 inch (8 m) rangefinders, the others had 236 inch (6 m) rangefinders.

6) "E" Model mountings had two hoists per gun, while the other Models had one.  The second hoist was intended to support higher angle (anti-aircraft) firing by making it easier to change ammunition types, but they resulted in a larger turret trunk, a larger lower chamber, increased turret weight and added crewmen.  As loading was performed at +5 degrees and the training and elevation speeds were low, the reality was that these mounts were of little use for anti-aircraft defense.  The maximum elevation of the "E" Model was +70 degrees, but the elevating and recoil mechanisms proved to be fragile and it was found that +55 degrees was the maximum practical elevation.  The later, improved "E₁" and "E₂" mountings were designed with a maximum elevation of +55 degrees.

7) The gun axes were 74.8 in (190 cm) apart.

8) As originally completed in the 1920s, the Model C and D mountings used pusher hoists that effectively created a continuous powder train between the gun breeches and the magazines.  During reconstruction in the 1930s, the pusher hoists were replaced by more flashtight "bucket" hoists on an endless chain.  These proved their worth when a flareback wrecked Turret 2 on Ashigara in 1935.  Although 41 men were killed or injured, the flash did not penetrate down into the magazines.

9) E model mountings (and the B model used on Akagi and Kaga) differed from earlier mounts in having flat roofs instead of sloped roofs and in that the rangefinders were partially within the mounting instead of being superimposed.  The entry doors on the rear of these later mountings had a curved top while earlier doors were rectangular.