How should I store my inkstick, and does it expire?

The simplest care is to keep the inkstick in its box after use, which protects it from sudden temperature and humidity changes — a cool, dry place away from direct sunlight is ideal.

An inkstick is sensitive to fluctuations in temperature and humidity, and extreme swings can cause it to crack, so avoid humid bathrooms or spots near heat sources.

Properly stored inksticks don't "expire" the way liquid ink does — in fact, aged inksticks (koboku) are valued by collectors and calligraphers, since the glue gradually loses some of its binding strength over time, giving the stick a smooth ink with a distinctive hue.

If a stick does develop a small crack, this doesn't necessarily make it unusable for practice.