The fifth hell is that of the Hell of Great Wailing located beneath the Hell of Wailing and is the same size. The torment in this hell is ten times more severe than that in the above mentioned four hells (Hell of Regeneration, Hell of Black Ropes, Hell of Crushing, Hell of Wailing).

Suppose 800 years in the human world equals to one day in the Creating Enjoyment Heaven, the fifth heaven in the realm of desire, where inhabitants live for 8,000 years. Suppose one day in this hell corresponds to 8,000 years in the Creating Enjoyment Heaven, those sinners who fall to the Hell of Great Wailing have to suffer for as long as 8,000 years.

Ken Hōbō-shō, A Clarificaton of Slandering the True Dharma, Writings of Nichiren Shōnin, Doctrine 3, Pages 109.