NYT on forced confessions by Japanese police
It might be true the article 38 of the consitution defends the right in question.
No person shall be compelled to testify against himself.
Confession made under compulsion, torture or threat, or after prolonged arrest or detention shall not be admitted in evidence.
No person shall be convicted or punished in cases where the only proof against him is his own confession.
But I sometimes hear that in some cases interrogations are actually severe, not that they are tortured physically, but that verbal abuse and the long time detention will operate against the suspect beyond a reasonable limit..
As a side note, as an anti-Japan propagandist, Onishi was sure to fail to mention Japanese system in which the suspects in detention actually have right to help from lawyers for free.