The Government, the power industry and the academic community seriously underestimated the potential risks. The timing of the near nuclear disaster at Fukushima Daiichi could not have been more appropriate.
In only a few weeks the world will mark the 25th anniversary of the worst nuclear plant disaster to affect our planet - Chernobyl in Ukraine. A major core meltdown released a deadly cloud of radioactive material over Europe and gave the name Chernobyl a terrible resonance.
It is clear that the name Fukushima came perilously close to achieving similar notoriety.
However the real embarrassment for the Japanese Government is not so much the nature of the accident as the fact it is clear authorities were warned long ago about the risks of building nuclear plants in areas of intense seismic activity.
Several years ago, seismologist Ishibashi Katsuhiko warned such an accident was highly likely to occur. Nuclear power plants in Japan have a "fundamental vulnerability" to major earthquakes, Katsuhiko said in 2007.
The Government, the power industry and the academic community seriously underestimated the potential risks posed by major quakes.
Katsuhiko, a professor of urban safety at Kobe University, has highlighted three incidents at reactors between 2005 and 2007.
Atomic plants at Onagawa, Shika and Kashiwazaki-Kariwa were struck by earthquakes that triggered tremors stronger than those the reactor had been designed to survive.
In the case of the incident at the Kashiwazaki reactor in northwestern Japan, a 6.8-scale earthquake on July 16, 2007, set off a fire that blazed for two hours and allowed radioactive water to leak from the plant.
No action was taken in the wake of any of these incidents, despite Katsuhiko's warning that the nation's reactors had "fatal flaws" in their design.
Japan is the world's third largest nuclear power user, with 53 reactors that provide 34.5 per cent of its electricity, and there are plans to increase provision to 50 per cent by 2030.
But its nuclear industry is bedevilled with controversy. In 2002 the president of the country's largest power utility was forced to resign after he and other senior officials were suspected of falsifying plant safety records. Nor is the nature of its reactor planning inducing much comfort.
The trouble is, says Katsuhiko, that Japan began building up its atomic energy system 40 years ago, when seismic activity in the country was comparatively low. This affected the designs of plants which were not built to high enough standards, the seismologist argues.
Since then, Japan has experienced more serious quakes as tension has built up on tectonic plates, culminating in Friday's devastating earthquake, the worst in Japan for more than 100 years. The result was an incident that came perilously close to triggering a nuclear meltdown.
Starved of coolant, the reactor would have heated up dangerously until its fuel rods melted and released a cloud of highly radioactive material.
Not surprisingly, the International Atomic Energy Agency is urgently seeking details of what happened at Fukushima. The rest of the world - which includes many countries that are preparing significant nuclear expansion plans - will be looking very closely at what it finds.