As early as the 16th Century, foreign traders recorded for commerce was cast into tin ingots of fixed weight and used for all major transactions in the bazaar (market place) as a form of currency.The value of each ingot depended upon it's weight, thus the shape and size of each ingot was of little consequence.Most of the ingots were cast in Perak.These tin ingots circulated extensively in Perak,Selangor and Negeri Sembilan over a very long period.They were also acceptable in the neighboring Malay States in the Malay Peninsula as well as in Sumatra.
The earliest ingots were made in simple sand moulds and were cast in the shape of conical cylinders, rounded cones or cones decorated with raised ridges running from top to bottom which gave them the appearance of being 8 sided. This was followed by mount shaped ingots called "Chandi".
Gradually these tin ingots developed into the shape of sawn off four sided pyramids with flat tops known as the 'sugar loaf type'. Later, pyramids or 'pagoda-shaped' ingots were cast with wide thick rims and flat tops.
The tops of these pagoda shape tin ingots were sometimes decorated with one of the many varieties of the 'tampok manggis' i.e. mangosteen rosette or calyx. This design may have been intended to indicate the mint or place of manufacture.
In Perak it became the practice to price all merchandise in smaller tin ingots called 'Bidor'. Their weight was 2.1/2 Katis (1 Kilo 512.5gm) and these were equivalent to 25 Cents of the Spanish silver dollar (8 Realers).
Gradually the term 'bidor' became so popular that most of the tin ingots of Perak, Irrespective of their weight, came to be called 'Bidor'.
These currency blocks of tin ingots were used for internal trade as well as in international commerce.These tin ingots continued to circulate until the mid 1850's when they were gradually replaced by the minor coinages of the Dutch and British East India Companies.