Why hasn’t Japan’s government debt wreaked havoc (yet)?

This is from 2014.

Authors use Reinhart-Rogoff argument that huge government debt-to-gdp ratio hurts growth even if it's domestic debt. It had huge political impact and many government adopted austerity-policies.

It's the most famous errors in economics. There was Excel spreadsheet errors that completely invalidated the argument. The methodological errors became just a side show.