The Tortoise Shree Yantra is deeply rooted in all Yantras, and has a deep connection with human history since ancient times. Apart from this, it has the strongest roots in the field of instruments, and thus it is also considered as the most valuable and most important instrument.
It is also said to be an imitation of and inspired by the Shree Yantra and is also known as the "Kurma Prithvi Meru Shree Yantra". Which means, that the tortoise is mounted on the back of the Shree Yantra. This is called the three-dimensional projection of the great wheel. It is considered very auspicious when placed in temples, worship rooms and commercial places.
It is also said that the Maha Meru Shree Yantra contains within itself the energies of all other Yantras and of all traditions. The yantra is made on the back of a tortoise with eight petals. Like there is a lotus flower in every instrument. Because it is the most sacred flower, and one originated from the navel of Lord Vishnu and the sitting place of Lord Brahma.
It has been worshiped since Vedic times for good and positive blessings, and is considered to be of the same importance as the Shree Yantra. It bestows all divine blessings to the worshiper and removes all negative influences from life. Like Shree Yantra it also removes all the obstacles in human life.
Worshiping this Yantra brings all kinds of goodness to a person, and for this it has been worshiped by many saints and sages since the seventh or eighth century.
Apart from this, it also has more importance in Vastu art. That is the reason, that it is placed at the center or top of the house and temple. So that the surrounding environment can be made healthy, wealthy and intelligent. It is the divine protector of human life for being very powerful and living on both water and land.