Reducing and Increasing Fire
Reducing and Increasing Fire ( 進退抽添 Jintui Choutian ) is a basic term of Daoist alchemy. It is a key point in mastering the fire phases. Under the elicitation of the moon's changes from crescent to fullness, Daoists find alchemical process as a process of transformations between Yin and Yang. Therefore, the control over the fire phases ( 火侯 Huohou ) focuses on the changes of Yin and Yang. Increasing Yang fire involves starting the fire and enhancing it. Reducing Yin fire involves weakening the fire and nourishing in warmth and ceasing refining. The fire phases also include taking out old fire and adding new fire.
The reason that alchemical fire phases stress the process of increasing and reducing fires lies in the rule of the changes of Yin and Yang which are innate in the universe. The Way of alchemy is in accordance with the universal rule and thus should follow the universal rule of changes of Yin and Yang. The Transmission of Dao by Zhongli Chuan and Lü Dongbin ( 《鍾呂傳道集》 Zhonglu Chuandaoji ) says: Heaven and Earth circulate, the weather cycles between hot and cold, the sun and moon go and come. These go round and round. Alchemy is just like the sun and moon in the changes of Yin and Yang. This goes for not only outer alchemy but also for inner alchemy. In order to illustrate the alchemical fire phases, Daoism introduced the numerology of the Book of Changes . As early as the end of Han, the Three Ways Unified and Normalized of the Book of Changes ( 《周易參同契》 Zhouyi Cantongqi ) had established the world's earliest mode of digital manipulation in expressing the fire phases with the 64 hexagramms of Book of Changes. Later alchemists greatly expanded on this aspect. Zhongli Chuan and Lü Dongbin of the end of the Tang and the Five Dynasties especially focused on the fire phases of inner alchemy. The contents about fire phases in the Transmission of Dao by Zhongli Chuan and Lü Dongbin is very significant in the development of Daoist life-nourishment theory.