After the partisans takeover the continental part of Croatia and before the outcome of new stamps, payment in cash was used. In the first period the tariffs from the Split provisional issue were applied (10kn for stationery, 20kn for letter and 30kn for registration).
Note that such postal items sent from the continental Croatia (and especially from Srijem and Slavonija) are classified as forerunners of the 1945 Zagreb provisional issue.
Forerunner of the 1945 Zagreb provisional issue, registered letter sent from Vinkovci (29.V.45) to Stari Bečej - Bačka (31.V.45) via Beograd, properly charged of 50kn in cash (Split tariff: 20kn for letter and 30kn for registration), censored by the military censor in Vinkovci.
Payment in cash
Military censor mark.