This kata came down to the Shotokan karate syllabus from Seisho Arakaki, a Naha te master. Unusually though it was not introduced by Funakoshi sensei but by his son, Yoshitaka 'Gigo' Funakoshi, a man many people believe to have played a key part in deepening the stances of Shotokan an making it more dynamic and 'harder' in style as compared to its Okinawan roots. Still, this was another kata that Funakoshi sensei tried to change the name for mainland Japanese, and this time he succeeded. Formerly the kata was called Hakko.
This form itself is a very powerful kata. The name means 'Tranquil Force' and the kata promotes the use of a wide, deep, powerful stance that roots the practitioner to the ground making him supposedly immovable in the face of danger.