Stomach

In everyday Japanese hara means "stomach" or "belly" and this is what will come to people's mind when they see this design. However hara also has special meaning in Japanese and Chinese cultures. For more information see the Wikipedia article Dantian.

Master Takase also discusses this in detail in an excellent article Hara: Master Calligrapher Eri Takase on the Art and Energy of Japanese Calligraphy.