In the cosmology of ancient India, a mountain named "Sumeru" stood at the center of the universe. The Sumeru altar thus represents the whole of existence; and the statue or image of a Buddha or Bodhisattva on top of the altar reminds us that our unborn and undying True Refuge is never separate from us even for a moment, regardless of the circumstances in which we find ourselves. In the words of Great Master Keizan, "The VERY TRUTH is now here, eternally, beyond all ages."
Rev. Master Jiyu Kennett explained the traditional hourglass shape of the Sumeru altar as follows: The lower steps of the altar represent the progress that one can make in spiritual training relying on one's own will power. The higher steps—the overhanging steps that seem impossible to climb—can only be climbed by means of deep faith in Buddha Nature. The middle section between the upper and lower steps thus represents the spiritual surrender of the lesser self to the True Self—willfulness converting to willingness.