20 Baht - Rama VIII Series 6, type II waves watermark

Thailand's Survey Department — primarily a mapmaking and cartographic unit of the armed forces — became an emergency currency printer during the Japanese occupation, when normal banking infrastructure had collapsed and prewar printing arrangements were impossible to maintain. This note dates to the final year of that arrangement, 1945, with the occupation ending in August of that year. The type II wavy-line watermark variation reflects incremental changes made during production runs that were never fully standardized, accounting for the multiple watermark states now documented within P#53A alone.

The absence of the printer's name in some watermark impressions is not an error — it reflects a deliberate or practical omission during specific pressings, now used by collectors to distinguish sub-varieties.