The Series 661 is where they introduced the $20 denomination, which took the place of a lot of $10s so finally the $10 was rare.
Here,s a few of mine like promised the Series 691 $5 has a population of only 3,200,000 and is a very rare note easily in my top 10 these examples our even rarer one from PCGS in 67PPQ and one from PMG in 68EPQ only (2) examples known at PMG
Here is my $10 from the same Series another top 10 and rarely seen in any grade this example is 65PPQ again has the same population as the $5 1st series 1,600,000 and 2nd Series 1,600,000
I've always been partial to the Series 691 $5 reverse vignette, but the one on the $10 looks like she stepped out of The Munsters or Addams Family.
many notes are very similar if not out right identical ! the Series 691 and the Series 541 are prime examples only the color is different with slight variations.
Here,s a tuffy, and in my top 5, Series 471 $5 a real rarity in any condition this 30PPQ example does have decent eye appeal even thogh it doesnt make my 53PPQ requirement
here,s a couple of notes from my Series 681 set which in fact with the exception of the $1 (28,000,000) and the 5 Cent and 10 Cent notes (14,112,000) each the rest have really low production numbers the lowest being the $10 at (3,200,000) in addition many of these notes were destroyed by Army finance, so true numbers of whats actually out there is any ones guess, but here is my blue chip example in 69PPQ which is the only note graded this high by either PCGS or PMG as a matter of fact this note was graded way back in 2006 !!
The BEP and DoD didn't really come up with a lot of "original" designs and often times they used recycled vignettes from earlier series, or even foreign notes like the Bank of the Philippine Islands notes. Ceres on the Series 521 previously appeared on a Standard Bank of Canada $5 from 1919. The lady on the reverse of of the Series 661 note previously appeared on a Bank of the Philippine Islands 50 Peso note. The vignette on the reverse of the rare Series 661 $10 previously appeared on the Series 1902 National Bank $20