A claim may be assigned; provided, however, that this does not apply if its nature does not permit the assignment.
債権は、譲り渡すことができる。ただし、その性質がこれを許さないときは、この限りでない。
Even if a party to a claim manifests the intention to prohibit or restrict the assignment of the claim (referred to as the "manifestation of intention to restrict assignment" below), the validity of the assignment of the claim is not impaired.
当事者が債権の譲渡を禁止し、又は制限する旨の意思表示（以下「譲渡制限の意思表示」という。）をしたときであっても、債権の譲渡は、その効力を妨げられない。
In the case prescribed in the preceding paragraph, the obligor may refuse to perform the obligation to a third party such as the assignee that knew or did not know due to gross negligence that the manifestation of intention to restrict assignment was made, and may duly assert against the third party any event that results in extinguishment of the obligation such as payment to the assignor.
The provisions of the preceding paragraph do not apply if the obligor does not perform the obligation, and the third party prescribed in that paragraph makes a demand to the obligor for the performance to the assignor by specifying a reasonable period of time, but the obligor does not perform the obligation within that period.