Thank you for the report. English translation has the following text and I guess you are right at [0] . The tracker deals with English translation. Please consider reporting this to https://github.com/python/python-docs-ja which also accepts PR.

[0] https://docs.python.org/3/library/collections.html#collections.deque.rotate

    Rotate the deque n steps to the right. If n is negative, rotate to the left.

    When the deque is not empty, rotating one step to the right is equivalent to d.appendleft(d.pop()), and rotating one step to the left is equivalent to d.append(d.popleft()).