Inspired by the Kotok-McCarthy-Program, Greenblatt thought he could do better and he succeeded to do so. More recently, Robert Hyatt, who had a chance to talk with Greenblatt several times, mentioned Mac Hack's hash function used a series of xor operations on occupied squares. While Zobrist mentions Mac Hack VI used a 32K hash table, he does not made it explicit that Mac Hack used this divide technique. Further the quotient may occupy several words as well, thus most of the transposition table would be occupied by these keys if type 1 errors were to be avoided. However, the integer which describes the board may occupy many computer words, and the divide will be complicated and slow. In his 1970 paper A New Hashing Method with Application for Game Playing, where he introduced Zobrist hashing, Albert Zobrist mentions a possible hashing method to obtain an integer which describes the board configuration, and then to divide the integer by the hash table size and use the remainder as hash address and the quotient as key. It regular searched five plies plus quiescence search and a conditional intermediate layer if own pieces were en prise. Mac Hack VI was the first chess program which uses a transposition table, but not yet iterative deepening. The number VI refers to the PDP-6 machine for which it was written. Over time, it became a hack in the sense of Hackers: Heroes of the Computer Revolution, a book by Steven Levy in which Greenblatt appears. The name Mac Hack VI comes from Project MAC a large sponsored research program located at MIT.

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