The Japanese had a modest exploratory research program. They were, in other words, looking into the question of whether nuclear weapons could be built, and whether they should be worried about in the short-term. They concluded that they were not a big short term worry.

Exploratory programs don't produce nuclear weapons. They produce, at best, a push for bigger programs. The Japanese program never got out of the exploratory phase — they designed some centrifuges and some equipment, but they never followed through on even building it, much less building it to the scale you'd need to get results. The Germans, by contrast, did try to build some things — experimental reactors — so their program was "ahead" by this calculus. But neither the Japanese nor the Germans moved to what we might call the "production" phase, where they were actually trying to generate fissile material in quantity, much less fashion it into a bomb.

To put it succinctly: they were not even remotely close to getting an atomic bomb during World War II. They were not, frankly, even trying to do it. This is not that surprising, given the difficulties and risks involved — no nation actually put in the necessary resources and effort to make atomic bombs except the United States. To get an understanding of what that requires, the US employed almost 1% of the entire civilian labor force (about 600,000 people) in their effort, spent $2 billion 1945 USD on it (between tens and hundreds of millions of dollars per month), and created laboratories that housed literally thousands of advanced scientists working on the project full-time. The German and Japanese programs had nothing comparable — theirs were tiny programs subsisting on thousands of dollars and dozens of researchers. You might not need the full Manhattan Project scale to make an atomic bomb today, but you definitely did need it in the 1940s, especially under short (e.g. under 5 year) time scales.