Re: COPS! In the US, the beat you to death. In the Japan, you must confess.
Standard operating procedure over there, I hear.
I don't know why you're getting downvotes, as what you say does seem to be accurate. From the Wikipedia page on the Japanese Criminal Justice system:
Confession in Japanese criminal investigation
Many Western human rights organizations alleged that the high conviction rate is due to rampant use of conviction solely based on confession. Confessions are often obtained after long periods of questioning by police as those arrested may be held for up to 23 days. This can, at times, take weeks during which time the suspect is in detention and can be prevented from contacting a lawyer or family.[3]
And here's a link to a BBC article on the same topic that also suggests reasons why people confess.
These were the two top links when I searched for "japanese police confessions", btw, not just links I cherry-picked to support the argument.