  The problem of the construction of magic squares occupied many mathematicians
of the 17th century. The Polish Jesuit and polymath Adam Adamandy Kocha\'nski
studied this subject too, and in 1686 he published a paper in Acta Eruditorum
titled "Considerationes quaedam circa Quadrata et Cubos Magicos". In that paper
he proposed a novel type of magic square, where in every row, column and
diagonal, if the entries are sorted in decreasing order, the difference between
the sum of entries with odd indices and those with even indices is constant. He
called them \emph{quadrata subtractionis}, meaning squares of subtraction. He
gave examples of such squares of orders 4 and 5, and challenged readers to
produce an example of square of order 6. We discuss the likely method which he
used to produce squares of order 5, and show that it can be generalized to
arbitrary odd orders. We also show how to construct doubly-even squares. At the
end, we show an example of a square of order 6, sought by Kocha\'nski, and
discuss the enumeration of squares of subtraction.
