Hajime wrote:- a vanilla- or x-samurai cannot have an empty middle grid - as experienced by m_b_metcalf
a vanilla samurai needs 5 givens and an x-samurai needs at least 1 given in the middle grid
It is clear that for a standard samurai at least two clues are needed in the central box (box, not puzzle). As quoted elsewhere: "In a limiting case, sufficient information can flow between the five sub-puzzles for the four corner ones to be solved completely. What is left is a central puzzle with its corner boxes full. We know that one other box must contain some clues, namely the central one (otherwise there are pairs of empty rows/columns), and that it must contain at least two clues positioned such that there are not two rows (or columns) intersecting it [the box] that are empty.". Why, in practice, five seem to be necessary I do not know.
Regards,
Mike Metcalf
