Japan's world war 2 technically went off with a blast in 1937 when they fought against the Chinise...
The Chinese were very brave and even had extensive help from Germany... great irony yes but war is never simple...
At epic battles like Shanghai it is well documented how it was like the "Stalingrad of the East" when generalissimo Chang KaiShek tried to open a Northern front against the Japanese Imperial Forces in Manchukou (Manchuria)
This battle was famous because Chang threw his best German trained and equipped divisions like the legendary 88th which had soldiers dressed and kitted like Wermacht fighting IJA Marines and Infantry battalions in the Streets of Shanghai itself.
Also the size of the conquests of Japanese forces in World war 2 was huge... in a few Months IJA and IJN had snatched 1 fifth of the Worlds surface from the Allied forces of Britian, Dutch, American and Australians... while also thrashing the French in Indo China as well...
Many people have negative attitude towards Japanese forces, not surprisingly because of terrible brutality by some members of IJA but we must remember most IJA officers hated those seemingly "Fascist" characters as well... while vast majority simply followed orders... anyway aside from politics and the horror of post combat prison/death camps.
Japanese forces are also special because of some unique characteristics to their forces. Chronic lack of heavy firepower, air support in later years and also lack of sufficient heavy artillery and armour meant the IJA had to develop specialised jungle warfare tactics, aggressive patrolling and counter patrolling, booby traps, ambushes and other grisly aspects of guerrilla warfare.
Plus the asymmetric nature of Japanese fighting tactics is a harsh thing for many to learn but the tactical rewards are very good and one can easily transfer such skills. I think there is a huge potential in this aspect.
The French colonies fought well despite the Government leaving them to it... Also the Dutch gave a good account of themselves too. France beat Thailand but couldn't hope to stop the Japanese after the ABDACOM fiasco