The Sea Route of Silence (沈黙の航路, Chinmoku no Kōro) is an unusual area in the middle of the vast stretch of ocean south of the Land of Lightning. As the name suggests, most part of the sea in this region is dead without any flowing water. It is surrounded by a mysterious magnetic field where even the steamships cannot function. However, there is a strip of narrow canal where a current continuously flows. The ships are propelled forward by this current but are unable to change their course or alter speed after entering this canal. According to Aoba Yamashiro, there is no wind or fish inside of it. Naruto Uzumaki later finds out that there are even no birds. Due to the tranquillity of the sea in this region, even Might Guy's sea-sickness fades away.