The Japanese had both the capacity and the geopolitical position to develop modern long range strategic bombers.
In the late 1930's, Mitsubishi responded to the IJN's RFP for a new land-based long range bomber with a four-engine proposal. The IJN nixed that and instead the G4M "Betty" resulted. Some secondary sources say that vestiges of the original design can be seen in the G4M's large fuselage, which does seem more appropriate to larger 4-engined bomber. Had the IJN accepted Mitsubishi's initial proposal, Japan could have had a reasonable-sized strategic bomber force. Later, the IJN did order the Nakajima G8N Renzan as a heavy bomber, but only a few prototypes were built.
For some reason, the IJA did not seriously consider heavy bombers after their experiments with the license-built Junkers G.38
However, Japan did not have the capability to build heavy bombers in the numbers required to mount a sustained strategic bombing campaign. To do so would have required cancellation or reduction of many other more valuable IJN types, such as multi-engine flying boats, carrier-based planes, and light/medium bombers.
Had the Japanese developed any modern four-engine bombers and put them into operation, it is likely they would be in relatively small numbers and probably used more as long range maritime reconnaissance bombers with a secondary strategic bombing role.