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=History=
The magic bitboard approach was motivated by [[Gerd Isenberg|Gerd Isenberg's]] multi-direction hashing technique [[Kindergarten Bitboards|kindergarten bitboards]] and probably by Gerd's and [[Tony van Roon-Werten|Tony van Roon-Werten's]] early trials to map line-wise [[Occupancy|occupancies]] by [[De Bruijn sequenceSequence|De Bruijn]]- or random number multiplication <ref>[https://www.stmintz.com/ccc/index.php?id=489834 rotated bitboards obsolete?] by [[Gerd Isenberg]], [[CCC]], February 26, 2006</ref> . [[Lasse Hansen]] had the idea to hash the up to twelve relevant occupied bits of '''both directions''' of a rook- or bishop movement simultaneously <ref>[http://www.open-aurec.com/wbforum/viewtopic.php?t=5015 Fast(er) bitboard move generator] by [[Lasse Hansen]], [[Computer Chess Forums|Winboard Forum]], June 14, [[Timeline#2006|2006]], Initial idea</ref> .
[[Pradu Kannan|Pradu Kannan's]] improvements to Lasse Hansen's initial approach was to introduce a [[Java]]-like, two-dimensional [[Array|array]] with individual size for each square and all it's relevant occupancies <ref>[[Pradu Kannan]] ('''2007'''). ''Magic Move-Bitboard Generation in Computer Chess'', as [http://www.pradu.us/old/Nov27_2008/Buzz/research/magic/Bitboards.pdf pdf]</ref> . Big savings in table-size - since many squares on either orthogonal or diagonal lines require less bits than others, especially considering the [[First Rank Attacks#TheOuterSquares|inner six bits]]. While center squares are more dense for rooks, it is the opposite for bishops <ref>[http://www.open-aurec.com/wbforum/viewtopic.php?t=5441 List of magics for bitboard move generation] by [[Pradu Kannan]], [[Computer Chess Forums|Winboard Forum]], August 23, [[Timeline#2006|2006]]</ref> .
