The Type 3 Chi-Nu (medium tenth) was the last tank to be developed from the Chi-Ha medium tank, and combined the improved chassis of the Type 1 Chi-He with a large turret carrying a 75mm tank gun. By 1943 it was clear that the Japanese army needed more powerful tanks, and work began on the improved Type 4 Chi-To (medium seventh), while the Chu-Nu was produced to fill the gap.
It was based on the chassis of the Type 1 Chi-He, which used a simplified version of the original Chi-Ha chassis, with thicker armour and a more powerful engine. The Chi-Nu retained the chassis and engine of the Type 1, and combined them with a new turret, containing the 75mm Type 3 tank gun.
This tank gun was based on the 75mm Type 90 field cannon, itself a license-built version of the Schneider cannon. The Type 3 tank gun had a 2.85m long barrel (L/38, or 38 times the calibre of the shell), and fired a 6.6kg armour piercing shell capable of penetrating 90mm of armour at 100 meters or 65mm at 1,000 meters. This gun was carried in a large hexagonal turret.
The low priority given to tank production by 1943 meant that the Type 3 did not enter production until 1944, when 55 were accepted. Another 89 were completed in 1945, bring the total to 144. The Type 3 Chi-Nu is not believed to have entered combat, having been kept on the Japanese home islands to resist the expected invasion.
Type 3 (1943) Chu-Nu (medium tenth)
Stats
Number produced: 144 (or 166)
Produced: 1944-45
Length: 18.5ft/ 5.73m
Hull Width: 7.66ft/ 2.33m
Height: 8.6ft/ 2.61m
Crew: 5
Weight: 18-18.8 tons
Engine: 240 hp Type 100 V-12 diesel
Max Speed: 24 mph/ 39 km/hr
Main Gun: 75mm Type 3 L/38 gun
Machine Guns: One 7.7mm machine gun
Hull
Front - 50mm
Side - 25mm
Rear - 20mm
Turret - 25mm
http://www.historyofwar.org/articles/weapons_type_3_chi_nu.html 
