Dandasana is so called because the spine resembles the staff carried by Indian renunciates who have achieved the title of swami danda. The staff itself is said to represent the spinal column and the way it forms the path for the energy of self-awakening. Dandasana is, therefore, considered to be the ideal asana for promoting strength and good form, which supports one's spiritual journey.
In addition to supporting the correct flow of energy in the body, this pose is considered to be good for helping one connect to the three bandhas, or "seals" or "locks." By simultaneously engaging mula bandha, uddiyana bandha and jalandhara bandha in dandasana, you create maha bandha, or the "great lock," which deepens the experience and awareness of the whole posture.
Dandasana is the first seated posture in the Ashtanga yoga primary series and, as such, forms the foundation for all other seated postures. More advanced variations of dandasana include ubhaya padangusthasana and utpluti dandasana.