Designed once the war had already begun and approved for construction in early 1944, the 4-ship Daikakuji class was to be the ultimate Kokoan heavy cruiser. Specifically designing a triple turret, The Kokoan naval design board took the main armament up from 10 to 12 guns while reducing the barbette numbers from5 to 4 compared to the senjo class cruisers.
Overall, the ships were to displace over 17.000T standard and almost 21.000T at full load. The twelve 203mm (8-inch) main guns were to be augmented by sixteen 100mm (3.9.inch) dual purpose guns in eight twin mounts, forty of the new 40mm anti-air machine guns (in 10 quad mounts) and up to 32 single 25mm machine guns. In addition four banks of quadruple torpedo tubes were also included, making the Daikakujis the most heavily armed heavy cruisers designed at that point, even edging out the similarly-sized Japanese Suribachi already under construction.
Armor protection was also increased compared to previous cruiser classes. The main belt reached a thickness of 152mm (6-inch) abeam the magazines and 140mm (5.5-inch) along machinery spaces. Transverse bulkheads thinning to 105mm (4.1-inch) connected the belt with the forwardmost and rearmost main gun barbettes. A 102mm (4-inch) upper belt extended at midship between the DP mounts. Main deck thickness was 76mm, increasing to 95mm over magazines and boiler uptakes. 35mm plating extended on the quarterdeck to the steering gear box, which was itself protected by 102mm (4-inch) of armor on sides and 50mm (2-inch) aft. Anti-torpedo bulkheads were 65mm (2.6-inch) thick, with a 2m internal bulge on each side for increased protection. Compared to previous Kokoan cruisers, which usually had only lightyle armed turrets, the Daikakujis saw the turret face armor increased to 127mm (5-inch), the sides to 76mm (3-inch), rear to 50mm (2-inch) and only the rear left at 25mm (1-inch). Barbettes were 100mm (3.9-inch)thick, and even the dP-guns hoists had 76mm (3-inch) of armor protection above the upper belt. The forward wheelhouse/conning tower was also protected by 100mm (3.9-inch) steel plates.
Engine-wise, eight oil-firing boiler powered four geared turbines with a generated power of 152.000shp, for a top speed of 34 knots. Endurance was planned at 9.500 nautical miles (17.594km) at 16knots. The ships were to fit the most up-to-date electronics and aircraft facilities as well.
Daikakuji specifications as planned (1944/45)
-Displacement: 17.360 t standard, 20.797 t full load
-LOA: 221,46m (726,59ft)
-LWL: 217,71m (714,27ft)
-beam: 23,40m (76,77ft)
-mean draft: 6,60m (21,65ft)
-Machinery: 8x Oil firing boilers, 4x geared steam turbines, 152.000 shp, 4 shafts
-Speed: 34 kts
-Range: 9.500nm at 16 kts
-Armour: main belt 152/140mm (6''/5.5'', inclined 20°in), upper belt 102mm (4''), transverse bulkheads 140/105mm (5.5''/4.1''), torpedo bulkhead 65mm (2.6'', protective internal bulge 2m on each side) main deck 95/76mm (3.7''/3''), quarterdeck 35mm (1.4''), steering gear box 102/50mm (4''/2''), main turrets face 127mm (5''), main turrets sides 76mm (3''), main turrets roof 50mm (2''), main turrets rear 25mm (1'') , barbettes 100mm (3.9''), DP guns hoist 76mm (3''), conning tower 100mm (3.9'', forward, no aft)
-Armament: 12x 203mm/50 guns (4x3, 126rpg), 16x 100mm/60 DP guns (8x2, 400rpg), 40x 40mm/60 AA-MGs (10x4, 2.000rpg), 32x 25mm/60 AA-MGs (32x1, 9.000rpg), 16x 610mm torpedo tubes (4x4, 8 reloads)
-Electronics: Type24 air search radar, Type33-Kai surface search and backup FC radar, TypeR5CD surface FC radar (2x1), TypeR12CAD air FC radar (4x1), TYPE A8TR jammer, Type64 RDF, standard IFF (2x1)
-Aircrafts: 3x E16A
Of the four planned sister only two had been laid down by the end of the war (Daikakuji in 1944 and Aratama in 1945) but Daikakuji was the only of the two whose construction had effectively advanced beyond the keel and a few frames. Works on Daikakuji stopped in 1947 as part of Koko's surrender terms. The ship was launched incomplete in 1948 to clear the slipway and was mothballed awaiting disposal. However, just like the Italians, Kokoan Naval officials took their fair amount of time to scrap their ships -somehow aided by a unexpected complacency by US observers- prioritizing the scrapping of older units and suprlus Destroyers, keeping the more recent units at the bottom of the "to do" list. This would have been a little more than a procrastination game however if the korean War had not broke out however. As the Korean situation shuffled priorities, the Kokoan armd forces were granted much more freedom as nearly all bans were lifted. Koko Kaijou (the postwar Koko no kaigun) enjoyed a similar treatement as well.
Daikakuji was towed back to drydock and works restarted after the design ad been accordigly modified to suit the more advanced times and technology. US-built radars and electronics were fitted in place of the Kokoan/Thiarian sets initially planned, removed from the design were also all 40 and 25mm machine guns, replaced with US-built twin 76mm pieces and 20mm Oerlikons. Even the 100mm DP battery was of an improved model, devoid of the short barrel life that plagued the original Kokoan and Japanese weapons. Aircraft facilities at midship were removed, and a pad for two sikorsky helicopters was moved to the stern. Such modified Daikakuji was finally commissioned in 1952. The last Kokoan all-gun cruiser and one of the last gun cruisers to be commissioned worldwide.
Daikakuji specifications as commissioned (1952), same as planned except:
-Displacement: 17.258 t standard, 20.774 t full load
-mean draft: 6,58m (21,59ft)
-Range: 10.000nm at 16 kts
-Armament: 12x 203mm/50 guns (4x3, 126rpg), 16x 100mm/60 DP guns (8x2, 400rpg), 16x 76mm/50 AA guns (8x2, 1.200rpg), 16x 20mm/70 AA-MGs (8x2, 9.000rpg)
-Electronics: AN/SPS-6 air search radar, AN/SPS-4 surface search radar, SM/CXBL height finder, Mark24 GFCS, Mark25 air FC radar (4x1), Mark35 air FC radar (3x1), Mark13 surface FC radar (2x1), 66AKJ TDY jammer, TDYa jammer, DBM/DBM-1 RDF (2x1), AN/SPR-4 ECM (2x1)
-Helicopters: 2x H-5/S-51
By the early 60's Daikakuji had recieved improved SPS-8, SPS-10 radars and electronics. The two smaller Sikorsky H-5s were replaced with a single, larger, H-34. All 20mm Oerlikon mounts had been removed, as it was for the bow-mounted 76mm mount which was often swamped and hardly usable in all but calm seas.
Daikakuji specifications as of 1962, same as previous except:
-Armament: 12x 203mm/50 guns (4x3, 126rpg), 16x 100mm/60 DP guns (8x2, 400rpg), 14x 76mm/50 AA guns (7x2, 1.200rpg)
-Electronics: AN/SPS-6 air search radar, AN/SPS-10 surface search radar, AN/SPS-8A height finder, Mark24 GFCS, Mark25 air FC radar (4x1), Mark35 air FC radar (3x1), Mark13 surface FC radar (2x1), URD-4 TACAN, DBM-1 RDF (2x1), SLR-2 ECM suite (3x1 AS-571, AS-570)
-Helicopters: 1x H-34/S-58
Daikakuji would recieve one large and extensive refit in the early 70's updating radars and electronics once again and being fitted with missile sistems -yet retaining most of its gun configuration-, ultimately remaining in active service until 1988. The ship then acted as a training vessel before being decommissioned for good in late 1991. After almost 5 year of mothballing the vessel was finally sent to the breakers for scrapping.