SOS: Secrets of Opening Surprises (13-Volume Collection) *Repost*

Secrets of Opening Surprises brings you a wide variety of unusual opening ideas. They may seem outrageous at first sight, but have proven to be perfectly playable. An SOS deviates very early from the regular lines in a mainstream opening, usually even before move six! That is why it is so easy to actually bring the variation on the board.

This package includes 13 volumes, from volume 1 to volume 13 (latest until now).