Was thinking the same, but wonder if an arrest in Japan is somehow different to an arrest in US for instance, and hence not quite as excessive as it immediately sounds.
That's about the same as US federal prosecutors, but it mainly means they don't even bother prosecuting unless they think it's a sure thing.
That said, the 99% conviction rate is a bit misleading in that the prosecution rate is pretty low (as low as 10%?). Seems as the prosecutors are picking and choosing slam dunk cases than sending cases through the courts to avoid not guilty verdicts.
https://en.wikipedia.org/wiki/Criminal_justice_system_of_Jap...
https://www.inverse.com/input/culture/report-japan-criminali...
The way things are, my tax dollars are being used to protect profits of companies that often themselves pay no tax.