The second Danish stamp, 2 Rigsbankskilling, was intended to be used for local mail in Copenhagen, being the only in city in Denmark large enough, to have a local mail service in 1851/52 (apart from Aalborg - Nørresundby).
The stamp came in to prints, 2a (Ferslew print, 1851 - burlage on copper plates) and 2b (Thiele print, 1852).
Almost all 2a's are mutely cancelled, while 2b are typically cancelled with numeral "1" (Copenhagen).
Very few 2 RBS-stamps exist with other postmarks than mute or "1" - numeral "34" (Copenhagen railway service) being the most "often" seen.
Below is a rare copy used in Schleswig-Holstein, cancelled by the Holstein railroad with numeral "170".
The stamp was in Carl Aage Møllers (BPP) private collection until 2012, where it was auctioned by Postiljonen (Sweden).
Cheers, Ole