According to the above quotation from the Anban jie 安殘解, there are two types of breath: in and out. However, when one is breathing in-out, the mind should be located at the centre of the mahā-bhūta. What is the meaning of the term "四大" mahā-bhūta? According to Digital Dictionary of Buddhism, 四大 means the four mahā-bhūta, which all physical substances are composed of. The four maha-bhuta are: 1. 土 the earth element (Skt. prthivi dhātu); 2. 水 water (Skt. ab-dhātu); 3. 火 fire (Skt. teja-dhātu); 4. 風 wind (Skt. väyu-dhātu). According to the Theravadin Abhidhamma, our physical body 色 (rūpa) is also comprised from the 四大 mahā-bhūta , which refers to the cycle of birth and death. Therefore, sometimes 四大 mahā-bhūta can imply the body of elements, 四大之身 mahā-bhūta rūpa.
The figure describes the four elements or four mahā-bhūta