1913, Start Aarau, 50c blue, yellow and magenta, two singles, one with nice offset on reverse and practically omitted yellow color, full OG, NH or LH (stamp with offset), VF, SBK #I, CHF600, Est. $150-$200 (Image)

1913 (April 6), Start Aarau, 50c blue, yellow and magenta, used on color official PPC No.2 from Aarau to Olten, in addition unused single stamp with OG, previously hinged, both are VF, SBK #I, CHF1,200, Est. $300-$400 (Image)

1913 (March 11), Basel, 50c blue, used on color PPC together with 5c green, addressed locally, top right card corner crease, still F/VF, SBK #II, CHF700, Est. $150-$200 (Image)

1913 (March 30), Bern, 50c red lilac, used on Oskar Bider postcard together with 5c green, all appropriate markings, in addition a single stamp, full OG, LH, both items are VF, SBK #III, CHF630, Est. $150-$200 (Image)

1913 (March 30), Bern, 50c red lilac, used on Oskar Bider postcard together with 5c green and black and orange label promoted Agriculture Exhibition of 1914, excellent quality, VF, SBK #III, CHF280, Est. $100-$150 (Image)

1913 (March 30), Burgdorf - Bern, 50c green on yellowish paper, used on Oskar Bider postcard to Bern together with 5c green, fresh and VF (H. Renggli certificate), in addition stamp of 50c dark green on white paper, appearing NH, but expertly repaired, SBK #IV, IVa, CHF1,200 for card only, Est. $300-$400 (Image)

1913 (March 30), Herisau, 50c blue, used on specially printed postcard together with 5c green, addressed to Zurich, some card faults, in addition an unused single (no gum), VF appearance, SBK #V, CHF1,500, Est. $250-$300 (Image)

1913, Langnau, 50c dark brown violet, usual rough perforation, nice centering, full OG, very light trace of hinge (appearing NH), VF, SBK #VI, CHF650, Est. $150-$200 (Image)

1913 (May 4), Langnau - Bern, 50c dark brown violet, used on Oskar Bider postcards together with 5c green, tied by special air post marking, mostly VF, SBK #VI, CHF1,400, Est. $200-$300 (Image)

1913, Laufen, 50c green, nice and fresh single, full OG, LH, VF, SBK #VII, CHF550, Est. $150-$200 (Image)

1913, Laufen, 50c green, ''Laufen - Solothurn. 28.9.13'' air post marking, stamp with full OG, mostly VF, SBK #VII, CHF2,600, Est. $400-$500 (Image)

1913 (April 27), Liestal, (30c) yellow and brown, used on special Liestal air post PPC together with 10c red, several repaired tears of the card (stamp is not affected), in addition an unused stamp with OG (shallow thin), F/VF appearance, SBK #VIII, CHF2,300 (stamp on the card is counted as used single), Est. $400-$500 (Image)

1913, Lugano, 25c blue green, red on gray background, a part of appropriate Lugano cancel, mostly VF, R. Berra- Gautchy certificate, SBK #IX, C.v. CHF2,500, Est. $400-$500 (Image)

1913 (June 8), Lugano, 25c blue green, red on gray background used on specially printed postcard to Milan together with 10c red, Posta Aerea ''8-GIUG-1913. Lugano'' postmark along with Mendrisio ''8.VI.13'' ds, mostly VF and scarce, SBK #IX, CHF2,800, Est. $500-$600 (Image)

1913, Sitten, 50c carmine, a single printed on wove paper, full OG, hinged, mostly VF, SBK #X, CHF700, Est. $150-$200 (Image)

1913, Solothurn, 50c claret, horizontal pair with strongly misplaced vertical perforation, full OG, NH, VF, small handstamp guarantee on reverse, SBK #XI, CHF1,000 as two common singles, Est. $300-$400 (Image)

BALANCE OF SWISS AIR POST ITEMS: 1913, Solothurn, 50c claret, a single stamp (LH) and stamp affixed over special postcard, in additional stationery postcard 5c green with Lausanne air post marking addressed to Bern, mostly VF, Est. $150-$200 (Image)

1938 (September 17-25), Philatelic Exhibition at Aarau, souvenir sheet of 20c+20c+10(c)/65c, used on Exhibition air mail cover along with multicolored vignette, tied by special ''23.9.38'' ds, blue Flight cachet and Bellinzona the same day arrival, VF, Est. $100-$150 (Image)