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The Story of Sissa
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There was once a victim of overwhelming numbers
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called King Shirham of India,
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who, according to the old legend,
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wanted to reward his grand Prime Minister Sissa for inventing
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and presenting to him the game of chess.
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The desire of the clever minister seemed very modest.
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“Majesty,” he said kneeling in front of the king,
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“give me a grain of wheat to put on the first square of this chessboard,
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and two grains to put on the second square,
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and four grains to put on the third.
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And so, oh King, doubling the number for each succeeding square,
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give me enough grains to cover all 64 square of the board.”
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“You do not ask for much, oh my faithful servant,”
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exclaimed the king,
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secretly enjoying the thought
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that his liberal proposal of a gift to the inventor
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would not cost him much of his treasure.
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“Your wish will certainly be granted.”
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And he ordered a bag of wheat to be brought to the throne.
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But when the counting began,
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it was found that the bag was emptied
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before the twentieth square was accounted for.
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More bags of wheat were brought before the king
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but the number of grains needed for each succeeding square
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increased so rapidly
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that it soon became clear that with all the crop of Indian
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the king could not fulfill his promise to Sissa.
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To do so would have required 18，446，744，073，709，551，615 grains!
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Assuming that a bushel of wheat contains about 5 million grains,
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one would need some 4×1012 bushels to satisfy the demand of Sissa.
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Since the world production of wheat averages about 2×109 bushels a year,
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the amount requested by the minister was that of the world’s wheat production
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for the period of some two thousand years!
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Thus King Shirham found himself deep in debt to his minister
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and had either to face the incessant flow of the latter’s demands,
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or to cut his head off.
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We suspect that he chose the latter alternative.