Well, the referred wikipedia article says a different story:
In murder, U.S. police arrested 19,000 people for 26,000 murders, in which 75% were prosecuted and courts convicted 12,000 people. In Japan, 1,800 people were arrested for 1,300 murders, but prosecutors tried only 43%. Had the allegation that Japanese prosecutors use weak evidence mostly based on (forced) confessions to achieve convictions been true, the larger proportion of arrests would have resulted in prosecutions and eventual conviction. But the opposite is true. In fact, the data indicates that Japanese prosecutors bring charges only when the evidence is overwhelming and likelihood of conviction is near absolute, which gives a greater incentive for the accused to confess and aim for a lighter sentence, which, in turn, results in a high rate for confession.