They tried, but failed.
A number of British-made single Bofors guns were captured in Singapore in 1942 and the Japanese proceeded to copy the design under the designation Type 5, but quality control was poor enough to cause severe reliability issues. Several modifications were made to try to resolve this and otherwise improve the weapon -- notably longer barrels and flash suppressors -- but they were never satisfactory and only a handful were built for trials.
(Remember that the U.S. had to make numerous modifications to the Bofors design to make it suitable for mass production. No one else, not even the British, managed to do so -- which is why the British version of the Bofors saw only limited use.)
Poland before WW2 buy license,but we still manage to made only 17 per month in 1939.Even worst,production of ammo hit even more problems,so we must sell 168 of those we made,becouse it would be no ammo for them.
We ended with 306 made,and,becouse we were too optymistic about how much ammo they use,many was abadonned when it was no ammo for them.
So,considering that Japan get guns,not plans for guns and machines to made them,i am not suprised that they failed.