The Board of Commissioners of Currency Malaya had issued two different notes of $1 and $5 (same design but different color) in 1940 and 1941. The $1 and $5 of 1940 issuance notes were printed in green and blue colors respectively. However, the $1 and $5 of 1941 issuance reversed the color of the its original design which made the blue color to $1 and green color to $5 instead. What would the British did that?
Indeed the British intentionally reversed the color of these two notes because it was believed that the German force had capture the shipload of $1 and $5 printed in 1940 during the war in Europe. Other source mentioned that an English merchant fleet carrying the shipment of the Malayan currency notes of $1 (green) and $5 (blue) issued in 1940 was sunk during the World War II. The immediate response from the British back then was to declare obsolete to these two denominations of currency. These notes are not for legal tender and circulation by the British Government.
It was until 1941, the new notes of $1 and $5 printed in reserve color of its original design was then re-introduced and widely circulated in the peninsular. Therefore, many of the Malayan notes we seen today are printed on 1 July 1941. Those Malayan notes printed on 1 January 1940 were relative rare and have higher collection values.
The original issuance of Malayan $1 note in 1940 was printed in green color
The revised issuance of the Malaya $1 in 1941 adopted the blue color