Secret currency
Secret currency (Yen: 密幣, mat bai, also archaically transliterated as Hipasian matbea or 'coin') was a type of complementary currency that has been historically used in East Catai, mainly in Yen regions, as a tender that acts in direct opposition to government-sanctioned currency or 'officials' currency' (官幣). Secret currency was used mainly by groups that opposed the state or were simply in illegal activities as a means to circumvent sophisticated state accounting methods developed in the Maengtau period and thus allowing transactions for illicit purposes without being monitored.
Secret currencies had origins in tokens used by secret societies of the Second Kingdoms Period, but sophisticated only in times of Maengtau, first developed by heretical forces that opposed the institution of the preceptor-emperor. The anti-Imperial movement forged distinctive bronze coins in the shape of artifacts discovered from ancient civilizations to not only give proof of their identity when encountering one another but also exchanged for favors or goods with, that evaded easily state monitoring. Later the system of secret currency developed further as the jianghu of the wide range of heretical, outlaw and illegal groups of Maengtau formed an entire parallel society (陰國, 'dark state'). With economic problems unfolding in the late 15th century, secret currencies entered widespread civilian use as part of an exploding black market. During the multi-preceptor period and even long after the fragmentation of the Yen, secret currencies were still very widely used, mostly as the dark state of the succeeding nations persisted.
Initially, secret currencies were nothing more than tokens established within single secret organizations. As the jianghu and the dark state developed however tokens from different groups were accepted beyond their own confines, which eventually evolved into a widely accepted secret tender. In Maengtau numerous secret currencies were in use. Fragmented East Catai, owing to the dark state's prolonged transnational existence, used the same series of secret currencies across its constituents for much of later history. The value of the secret currency fluctuated not only depending on general economic conditions but also on details as simple as the nature of the exchange since no central authority governed it. Gradual, general agreement with some universal convention or norm was the template for institution of changes to the secret currency system including its introduction. Most secret currencies were coins or coin-like items since banknotes were easily distinguishable as illegal tender by authorities.
The concept of the secret currency has inspired cryptocurrency development in East Catai, which, almost ironically similarly to its conceptual ancestor, is also currently mainly used for a wide range of illicit activities in the region.