Blank instrument is mentioned only marginally in the only provision (Article I, Section 10 BECA). It stipulates that if a bill of exchange/promissory note which was incomplete when issued has been completed otherwise than in accordance with the agreements entered into, the non-observance of such agreements may not be set up against the holder unless he has acquired the bill of exchange/promissory note in bad faith, or, in acquiring it, has been guilty of gross negligence.
The following characteristics of blank instrument may be inferred from this provision: Blank instrument is a paper signed by a debtor. The paper is determinated as a bill, parties have to consider it as pre-stage of future bill. Incompleteness of the paper is intentional, it means that according to the intention of parties, it lacks certain legal formality and it is joined with bill completion right agreed before. At the same time of transfer, the drawer of blank instrument enters into agreement on bill completion right with assignee. The written form of such an agreement is not obligatory; it can thus be concluded orally. Agreement on bill completion right often makes a part of pertinent contract (credit, leasing, or purchase).
Blank instrument can be thus defined as a paper determinated as a bill and its signator intentionally issued it as an incomplete one on condition that the bill completion right was agreed. The bill completion right agreement usually concerns bill sum and date of maturity.