During a healing session conducted by Yugoda, the elderly instructor demonstrated a technique of healing by guiding water through a network of chi paths carved into a life-size mannequin. An anxious General Fong made several attempts to induce the Avatar State in Aang when the team ventured to his base. One of his methods involved Aang drinking a chi-enhancing tea designed to increase the energy of a warrior ten-fold, which only caused an energy rush to course through him. During a duel in Omashu, Ty Lee first demonstrated the unique ability to block one's chi, thereby rendering the victim defenseless. By striking certain pressure points, she was able to strip Katara of her waterbending abilities temporarily.
Huu, a dweller of the Foggy Swamp, informed Team Avatar on how all living organisms were interconnected and shared the same roots. With this knowledge, Aang was able to tap into his chi and locate the currently lost Appa and Momo within the swamp. Guru Pathik demonstrated a similar ability to connect with his own chi paths and locate the Avatar in Ba Sing Se from his home at the Eastern Air Temple. Under Iroh's tutelage, Zuko was taught lightning redirection, a technique that enabled a firebender to absorb the lightning's immense energy within their body and release it in a more desirable direction. One crucial move in the redirection process is to guide the energy through the stomach, described by Iroh as one's "sea of chi". While practicing the motions for lightning redirection, Iroh asked whether the prince could feel his chi flowing throughout his body to which the latter replied yes.
Combustion Man, an assassin hired by Zuko to eliminate Aang, had the deadly ability to detonate explosions at will from a third eye tattooed on his forehead. Being struck in the third eye would temporarily result in his chi being disrupted and failure to trigger an effective explosion, which ultimately led to his demise at the Western Air Temple. While residing on the Black Cliffs, Katara attempted to calm an unsteady Aang by guiding him through exercise routines in a hot spring, which would enable one to feel their chi paths flowing smoothly.
The anti-bending Equalist organization has demonstrated the ability to block one's chi. The Dragon Flats borough, located in one of Republic City's residential areas, had one particular chi blocking training facility where nonbenders were taught the method in secrecy. Their members have immobilized several victims, including Avatar Korra, with this technique.
During her stay at the Foggy Swamp, Toph Beifong taught Avatar Korra how to tap into her chi and locate others. When she was back in Republic City, she used this ability to track down a kidnapped Prince Wu via the city's Spirit Wilds and to receive a vision about Kuvira's army hacking away the roots of the banyan-grove tree.
There is a deep connection between chi and bending, as bending is merely the ability to manipulate one's chi to the point where the energy can extend beyond the body and interact with the environment. Due to chi, the four bending arts are truly one and the same.
Enlightened individuals, such as Guru Pathik and Huu, further explained the concept of chi as the life energy that dwells inside every living being connecting them to each other, their surroundings, and the universe as a whole. Different parts of the human body contain concentrated clusters of chi, better known as chakras, or "pools of energy" as Pathik called them. When unlocked, these chakras are crucial for the Avatar to achieve his or her full potential, channeling his or her own energy as well as the energy from the universe.
Humans and higher animals have the potential to become deeply connected to one another, thus enabling Pathik, Huu, Aang, and potentially others to locate living beings out of sight and detect their thoughts and emotions by tapping into their chi.
Different types of benders, the Avatar, and even nonbenders, have shown skill in the art of chi manipulation, proving it to be a universal skill that can be learned by anyone.
Chi and the modern bending arts
Due to their heightened spirituality, all Air Nomads are born airbenders. The tattoos which they receive upon becoming airbending masters run along their chi paths. It is for this reason that Air Nomad Avatars' tattoos glow when they are in the Avatar State.
As Iroh explained, chi can be felt swirling around inside one's body, and the path can be changed to allow energy to flow in certain directions, which is the basic concept of lightning redirection, a move he invented by studying waterbenders. In actual waterbending, waterbenders directly use their own chi to mimic the moon's push and pull on the ocean tides. Combustion Man had the unique ability to gather chi from his stomach, the "sea of chi", and channel it to his forehead, creating localized explosions via a tattoo over his Light Chakra. Toph taught her metalbending students to feel their "gut furnace" as a means to focus their chi.
- Main article: Chi blocking
Ty Lee, having an unparalleled knowledge of the human body's chi paths and their weak points, used chi blocking to a great extent in battle to incapacitate or paralyze her opponents. She could even use this ability to disable another's ability to bend. Additionally, this art was utilized by members of an organization known as the Equalists, who employed this method as a means to counteract bending.
- Main article: Healing
A select few waterbenders are born with the ability to heal themselves or another by using water to redirect the chi in a person's body, revitalizing healthy chi energy and speeding up their healing process. Though powerful, healing cannot cure the effects of chi blocking and other injuries where one's chi paths are blocked or disrupted like internal wounds and birth defects. Katara, renowned for becoming the best healer in the world and being taught by Yugoda, a master in the art, was unable to counter Ty Lee's chi blocking on the fallen Terra Team soldiers.
- Main article: Bloodbending
Bloodbending can be used to sever the connection between a bender and their bending abilities, achieving the same effect as energybending. This technique has only been demonstrated by Amon and requires direct physical contact between the user's hand and the victim's forehead. According to Katara, the technique "severs" an individual from his or her bending through blocking active chi pathways, making it impervious to all methods of healing and its effects far more long-standing than chi blocking. Even so, only active chi pathways can be severed; Korra was able to use airbending because the pathways involved with the art were still closed when her other bending abilities were removed, and thus undetectable to Amon. However, the severed bending can be restored through the use of energybending, as shown by Aang and Korra.
- In real life, chi is a Chinese concept prevalent in traditional philosophy, medicine, and martial arts.