Huna is a reconstructionist religion inspired by the rich shamanistic spirituality, theology, and the magical and healing arts of the indigenous religion of the Hawaiian Islands. There is a major resurgence of the old traditions and practices as they are understood today. Regrettably, as the Christian missionaries were very effective in destroying much of the old knowledge, there is no way to know what is truly ancient. The basic concept of Huna is to live "the harmless, helpful life."
Generally speaking, Huna is a transformational system that includes meditation and breathing techniques, as well as visualization and dream exercises, chanting, and magical energy work. It is a religion orientated toward spiritual growth and personal development. It is a tradition that nurtures the Earth and enables a feeling of connection to all of life. The practitioner learns to direct energy back to Earth in return for his support.
Huna means "the secret", kahuna means "keeper of the spirit" or "priest" but is commonly used today to indicate an expert in a field. A teacher today is correctly called a "kumu."
Differences of Opinion
There is considerable disagreement concerning what is really Huna and what is not.
Some believe the teachings of the old ways have come down from the old kahunas. This position is more associated with family traditions and should be considered valid.
But there is more than one approach to Huna. Others believe that today's Huna is a modern mixture of old teachings and external sources. They believe Huna is a religious reconstruction that was created by several pioneers after World War II. Two leaders were the popular teacher Max Freedom Long and Oscar Brunler, who laid much of the foundation of today's theology. Neither Long or Brunler were ethnically Hawaiian, and they never claimed to be taught by or initiated by Hawaiian kahunas. In fact, Long taught that Huna was founded in Honolulu in 1872 and never claimed to be a kahuna.
It is very possible that Long and Brunler never met a kahuna. They were isolated on Oahu and it seems neither one made any effort to search the other islands for kahunas or families with ancient knowledge. It is now known that kahunas DID exist on the other islands with intact traditions, such as that of the Kahili family.
Nevertheless, Long and Brunler brought about a considerable amount of information that is today accepted by many as Huna.
New Age Variations
Note that there are haole (white Anglo) New Age Huna "instructors" that teach non-standard approaches, sometimes calling it "huna kalani", which is a non-traditional term not used by true Huna practitioners. The real ho'oponopono is taught by kumues. That does not mean that a New Age form of Huna cannot be of benefit to non-Hawaiian people, only that it may not be part of standard teaching or practice.
If you become interested in a specific Huna group, especially if you are not a native Hawaiian, do research to find a qualified group or kumu.