Japanese business will not start to conduct business until they trust the new party.

Japanese would think the result is the same, regardless of you exchange the written contract. They only want to carry out the business smoothly based on mutual trust, not on the paper.

Japanese contract is often for formality

If one side wants to draw up a written contact, the other party will take it as not trusted. Even if the written contract is made, it is often for formality. They apt to sign in the agreement without looking at it very closely.

Even if something disadvantages for one side are written in the contract, it does not always mean the deal work as written. Usually, they adjust based on common business practice by peaceful negotiation for their succession of the business.

If the business does not go well, the person in charge would be judged as lacking in human observation.