My four treasures of the study are a fountain pen, a pencil, an eraser, and a ruler.

The Schwarzschild radius is an important concept for understanding the characteristics of black holes.

The pre-order sale for the new game has started.

Bats use echolocation to fly in the dark.

He has a habit of reciting the Heart Sutra every morning.

He continues his training in search of the highest nirvana.

In Buddhism, the highest nirvana is considered to be the ultimate liberation.

We have started selling our new products by mail-order and online ordering.

I bought new clothes through mail-order.

His everyday matter is to wake up early in the morning and go jogging.