Head Stand (sirsasana) increases blood flow to the brain, improving memory and alertness but also a state of equanimity and balance. In hatha and some other yoga systems, sirsasana is called the king, and sarvangasana (shoulder stand) is called the queen. Just as a country cannot thrive without a strong and effective king (or head of state), a person cannot thrive without a strong and healthy brain. As for sarvangasana, regular practice of it is thought to create harmony in the nervous and endocrine systems, just as a mother creates harmony in the home and the queen creates harmony in her country. While shoulder stand (sarvangasana) can be practiced by itself, head stand (sirsasana) should always be practiced together with sarvangasana.