375rd Heinrich Köhler auction - Day 1

1920, Overprint issue 10 m. on 50 sk. + 6 m. on 50 sk. + 4 m. on 50 sk. green (position 28-30) within block of 6 with three regular stamps, tied by cds. “WILNO 20.1.21” to part of insured cover to Warsaw, the multiple with minor wrinkle and gum spot, horizontal fold through cover-front not affecting the adhesives, otherwise fine and very rare this being the only used multiple in existence, certificate Schmutz (2005)