Number of dice have been found in Mohenjo daro, Harappa and other Indus Valley Sites. The dice were found along with the some gaming pieces.
The dice are cube shaped. Some were made of terracotta and some from stone. These dice have one to six circular incisions on each of the six faces of the cube (the number of incisions on the faces of the cube don’t repeat).
(this image was obtained from Harappa.com – it is the picture a die found in Harappa)
The number of incisions on the opposite sides of the dice found in Indus Valley, always adds up to 7. Today as well the number of incisions on the opposite sides of dice always adds up to 7. There is no specific scientific or logical reason for this. It is a custom and a practice. It has become the standard in all dice.
Looks like this norm (opposite sides adding up to 7) originally started in Indus Valley and since then, we have continued to follow the same pattern.
It is quite fascinating how this standard with today’s dice has its roots in Indus Valley.
(this is a picture of a die found in Indus Valley sites – it is now in display at the Ashmolean Museum, Oxford)