 This stance is sometimes seen in kata, for example in Matsukaze.Han-Kokutsu-dachi (半後屈立, half kokutsu), also known as Sho Kokutsu-dachi (小後屈立, short kokutsu)
Shortened and raised kokutsu-dachi.The height of all these stances is, ideally, exactly the same, so that the transitions from zenkutsu to kokutsu (defense) or kokutsu to zenkutsu (attack) happen without loss of energy which would be necessary to move the body's center of mass up and down.