The launching of the Bt500 banknotes is based on three of the central bank's traditional frameworks, which are to commemorate present and past kings from Sukhothai, Ayutthaya, Thon Buri and Rattanakosin, keep up with new designs of banknotes to meet international standards and upgrade security features to make it harder for counterfeiters to make fake notes," deputy governor Tongurai Limpiti said yesterday.