Classed as a heavy bomber at the start of its career, the Mitsubishi Ki-21, known among the Allies as the “Sally,” certainly was a heavy lift in terms of effort for the Japanese Army Air Force during World War II. ICM has released a detailed 1/72 scale kit of the Ki-21-1b, an important early version that saw combat service in China early in the war.
Starting off, ICM suggests you attach the separate tail section to each fuselage half before assembling them together. This worked well, and the join required minimal cleanup.