Wri-In is to be stamped on several contracts. Kei-In is a Hanko to be stamped to prove that a contract is consist of several pages. In contrast to Kei-In, Wari-In needs to be stamped in the case that you have several contracts.
We usually make more than 2 contracts in such cases that both a contractor and a contractee need to keep an official contract each other. When you make 2 contracts, you need to write down that you make 2 contracts on the end of the last page of both contracts and pile up two contracts in such a way as to displace the position of contracts and stamp across two contracts simultaneously as the center of Hanko impression comes to the boundary between two contracts to be printed the impression divided in half then you can distinguish whether or not it is official.
When you pile up two contracts again, if there is no half impression on contractor’s contract, you will come to realize the contract without half of impression has been added without consensus illegally after concluding a contract.
What is the text of a wari-in? I know they are also found on diplomas of martial arts in Japan. Half the stamp is on the diploma, half the stamp is in the registration book. But I wonder, what is the text on the wari-in stamp?