The Alchemists in Fullmetal Alchemist use Alchemy for military purposes. It has it's own feel and means of practicing. However, Alchemy is not the only technique utilized in the anime. Across the desert in the Eastern nation of Xing, their version of Alchemy is known as Alkahestry.
Rooted in connection to the Earth's energy, Alkahestrists use and practice this form in differently compared to to Alchemists. Mei Chang is the only known practicer of Alkahestry in the anime, and is Edward and Alphonse's teacher on the subject. Alkahestry is also based on real Chinese Philosophy, which make the concept interesting to learn about. So what exactly is Alkahestry?
Xing: the Home of Alkahestry
Alkahestry is called Eastern Alchemy, practiced by the nation of Xing. It also referred to as Rentanjutsu in the manga. Ling Yao and Mei are royals from this country. Xing is across the Great Desert from Amestris, the country of the main characters Ed and Al. Both Ling and Mei travel to Amestris to conduct research on Western Alchemy for their own respective reasons.
Xing is made up of over fifty different clans, with an emperor ruling the entire nation. A daughter from each clan leader marries the emperor and bears him children. The present emperor has twenty-four sons and nineteen daughters, making Ling the twelfth in the line of succession.
The Form of Alkahetsry
Alkahestry is predominantly used in medical practices in Xing. This is a blatant contrast to Amestris, where Alchemy is used mainly for war ever since King Bradley became the Führer. Where Amestris view Alchemy as a scientific practice, Xing sees Alkahestry as a medicinal form.
Mei says that Alkahestry is about "reading the Dragon's Pulse", which humerously confuses Al. This means that it detects and uses the power that flows within the ground. The Earth is viewed as having energy or chi running through it. It is this understanding that roots Eastern Alchemy. The transmission of chi is what allows Alkahestry practices to work.
Where Alchemists use Transmutation Circles, Alkahestrists use Purification Circles. These circles allow for chi to flow and fulfill it's desired effect. It even permits the transmutations to be projected over long distances, a feature unique to Alkahestry.
Alkahestry does have its limits. Eastern Alchemy has not been proven to grant immortality, unlike its Western counterpart; at least, that's what Mei theorizes. This fuels Ling's Alchemy research, as he is looking for a way to achieve mortality for his father so that he carries favor as the next emperor.
Alkahestry in Fullmetal Alchemist
In episode 15 of Fullmetal Alchemist: Brotherhood, we meet Mei. She meets Scar for the first time after Yoki saved her while she was unconsious on the roadside. Mei sees that Scar is wounded, and offers to heal him. She draws a Purification Circle on the ground in chalk with a star inside, her multiple kunai piercing each point of the star. Scar's wound then closes up and is healed quickly.
Mei notices that Scar's intricate arm tattoo is indicative of Eastern Alkahestry. The technique is made up of understanding and utilizing the "Veins of the Dragon", the power that runs through the Earth. She notes that the tattoo draws power from Xing's Eastern Alchemy. This adds up because the tattoo is the product of Scar's brothers research in Western and Eastern Alchemy.
Alkahestry played an important role in the final moments of the anime. Mei uses the practice to heal Riza Hawkeye over getting the liquidized Philosopher's Stone. The combination of Alchemy and Alkahestry also resulted in the Father's defeat, as he could not control Alkahestry. Alkahestry also assisted greatly in helping Ed and Al to get their bodies back.