Mexico 1862 Rare Diagonal Bisect on Letter

1862: 2nd Issue: Hidalgo 4r black on yellow of 1861, DIAGONAL BISECT ON COVER on neat folded wrapper to Guadalajara. The bisect well tied by excellent strike San Luis Potosi datestamp. Of additional interest is that only a quarter of the listed bisects of this stamp are diagonal cuts, the majority being along the horizontal or vertical axes. A wonderful quality example of this rarity. Ex Dr Gene Scott & Gutierrez.