唐朝时出了个女皇武则天，
她手下有两个大臣最凶残。
武则天叫他们俩掌刑狱，
枉杀的忠臣良将无法算。
他们中一个叫做来俊臣，
另一个叫周兴的更阴险。
他俩专搞逼供信，
各种酷刑都备全。
周兴说凡是受审人，
没有一个不叫冤，
只有把他处死后，
大事化小小事完。
到后来有人向则天女皇报密信，
说周兴和别人要谋反。
女皇派来俊臣去审理，
来俊臣不由犯了难。
他知道周兴很狡猾，
挖空心思打一个主意在心间。
他先派人去请周兴来赴宴，
周兴来时欣欣然。
酒席间来俊臣装作很谦虚，
问周兴怎样处理疑难案。
并且问如果犯人不招供，
应该怎样去惩办。
周兴他并不知自己被人告，
得意洋洋畅怀谈。
他说：“若是犯人不招供，
你可在大瓮底下把火点，
烧得大瓮热烫人，
把犯人装进瓮里边。
囚犯即使再狡猾，
不招供的却未曾见。”
周兴的话儿未落音，
忽听来俊臣把人喊，
叫抬来一只大瓮缸，
底下及时把火点。
大瓮烧热来俊臣猛地拉下脸，
骂周兴：“有人告你个混蛋想谋反！
则天陛（bì）下有命令，
叫我来审理这一案。
今天你既然教了我好办法，
这就在你的身上做试验。
大瓮现在已烧热，
不坦白请你往里钻！”
那周兴立时吓瘫痪，
叩头认罪不隐瞒。
到后来“请君入瓮”作成语，
常形容，害人者往往自己遭惩办。
坏人设下圈套，最终自己朝里钻。
Please Step Into the Vat
In the Tang Dynasty（618—907A。D。），there was an empress named Wu Zetian，two of whose ministers were ruthless。Wu Zetian asked them respectively to take charge of courts and prisons。They had killed countless innocent loyal ministers and generals。One of the two was named Lai Junchen，the other one's name was Zhou Xing。Both of them were quite tricky in obtaining confessions，and made abundant means of punishment。
Zhou Xing once said that all those being tried surely had an inclination to claim they were being wronged。So only after putting them to death could we eventually make a big thing small and a small thing nothing。
Later a confidential message was passed to the empress that Zhou Xing was to rebel against the court with others。The empress ordered Lai Junchen to take up the trial，which put the latter in a dilemma。Lai Junchen knew that Zhou was very sly，so he racked his brains to weave a strategy。First he invited Zhou Xing to his home to feast，and Zhou accepted the invitation delightedly。In the course of the feast Lai Junchen pretended to be modest，and asked Zhou Xing to show him the efficient way of tackling those most complicated cases。He asked him，if a criminal wouldn't confess how could he make them。Zhou Xing didn't know he was being tricked，and he ecstatically talked his joyful talk。He said that if the criminal wouldn't confess，you could make a fire under a vat，and burn the vat until it was scorchingly hot。Then you would put the criminal into the vat。No matter how sly the criminal would be，no one had been seen to refuse to confess。
With these words still in the air，Lai Junchen shouted out to his assistants。He asked them to bring in a huge vat，and quickly made a fire under it。As the vat was heated Lai frowned and swore to Zhou，“Someone has charged you with being a scoundrel，having intrigue to rebel。Here Her Majesty has given me an order，asking me to try this case。Now that you have taught me the method today，I'll try it on you。The vat is heated up now，get into it if you are not willing to confess！”Zhou Xing was promptly paralyzed，kowtowed and made a confession at once。
Later the idiom“Please Step Into the Vat”was frequently used to describe a blackguard who will eventually be punished。The blackguard lays out a trap，and the blackguard steps into it himself。
