Spectacular block of four of the Kiautschou 30 Pf yacht postmarked K.D.Feldpoststation No. 2 ( Peking) during the Boxer Rebellion = so-called Petschili issue.
Michel German Offices in China No. P VI f
Stamp is signed v. Willmann (deceased, but always good), no faults
Michel CV is 4800.00 Euros (about $ 6800.00)
Most likely unique, definitely an Exhibition Quality item and a great China rarity.