A puja established by Shankara, to unite the different sects, practiced by the Smarta Sampradaya.
Five deities are worshiped together, Shiva, Vishnu, the Goddess (Parvati), Surya and a personal deity of the believer, usually Ganesha or Karttikeya.
The chosen deity is placed in the middle of the other four. If Shiva sits in the middle it is a Shivayatana Puja, if the Foddess sits in the middle it is a Deviyatana Puja etc.