From 《
资治通鉴·
唐纪》: Tang empress Wu Zetian's cruel official Lai Junchen (
来俊臣) asked the equally cruel Zhou Xing (
周兴) how to make stubborn suspects confess. Zhou suggested heating a large earthenware jar and forcing the suspect inside. Lai then revealed he had been ordered to interrogate Zhou himself — 'Please, sir, step into the jar.' Zhou confessed at once.