Land and climatic conditions: Japan and South Korea have relatively small land areas, most of which are mountainous areas with limited arable land. Potatoes need plenty of sunshine and suitable soil conditions to grow well. Therefore, these countries have relatively little land suitable for growing potatoes.

Eating habits: The main eating habits in Japan and South Korea have nothing to do with potatoes. They prefer rice, pasta and other grains as staple foods rather than potatoes. Therefore, compared with other countries, they have less demand for growing potatoes.

Agricultural policies and economic factors: Agricultural policies and economic conditions in Japan and South Korea may also have an impact on potato planting area. These countries may pay more attention to the cultivation of other agricultural products, or have other more profitable agricultural industries. Therefore, they may choose to grow other crops instead of potatoes on limited land.

These factors combined, resulting in relatively small potato planting areas in Japan and South Korea.