The Great Whole Body Relics Buddhas' Stupa (In Japan, its name probably is "Hookyoo into", or "houkyouintou") is a kind of Really Powerful and Special Stupa. It can help so quickly (almost the fastest way) to collect merits and purify really strong karma. This kind of stupa is rarely known in western.

The above shape of stupa is called as  Five-Element Stupa, Five-Story Stupa, or Five-Wheel Stupa, Five-Element Pagoda

Bodhgaya Stupa(Mahabodhi Stupa)