On the other side of the mountain you can get to the well-known river separating this world and the next (*1).

Gensokyo is on the side of the living, and Higan is on the opposite bank.

Many extinct fish inhabit the river, but it's said they're all ghosts.

Unfortunately, you cannot catch any of them.

The river is enveloped in a deep mist, so there is no day or night.

However, the mist shines faintly.

Jagged, moss-covered rocks break the surface in a number of places, lending to the otherworldly environment.

Since it's impossible to swim across (*2), the only way to cross the river is in a shinigami's boat.

However, the shinigami charge exorbitant fees for their services, so the living cannot cross (*3).

Once cross the river, you cannot return until your next life.

It's likely no-one has ever crossed while still alive.

The river barely flows at all, so it's a quiet, almost silent place.

Sometimes you can hear the cheerful songs of shinigami, but no other living thing can be heard.

Strangely, even as their boats travel over the water, the water itself makes no sound.

1: Incidentally, the place where the river flows isn't in Gensokyo, but you can get there from Gensokyo, so I am introducing it here.

2: For some reason your body won't float in the water, so you can't swim. Every boat sinks except shinigami's.

3: All one's worldly possessions is a pittance to the dead.