Everyone Says You Must Ask Before Reclining on the Shinkansen. The Railway Says There Is No Such Rule.

Why this phrase

JR Central's actual position is that there's no reclining rule on the shinkansen, just be considerate of the person behind you. The say-a-word-first custom drifted in from highway buses, where the seats are much tighter. So nobody will stop you. But one short line turns a stranger's stare into a cheerful どうぞ, and it works on planes and buses too. One takeaway: 「席、倒してもいいですか？」