Originally Posted by
ajnz
Interesting - I didn't know that.
That said, from the
URL you posted earlier it doesn't look like the $20 is a circulation note in the Portrait or Ship series. It's only mentioned in the Bird series.
It's a bizarre semi-commemorative note, issued in large quantities (3 million were printed), but not a regular circulation note. You could pick them up from banks at face value last year (max 2 notes per customer), and they're still available on eBay etc at a minor premium (~S$25).