China 1941 5 Yuan...counterfeit? Help Please

I took a look at all of the notes that you have linked. The notes that you purchased look good to me.

The serial number is an over print on the original printing. Weaker serials are a result of less ink on the stamp. It is normal.

The notes have 2 types of embedded colour fibers. I saw both colours on your notes. When you get the notes you should take a closed look to see if the fibers are embedded or printed on. They should not be printed on.

This note has a watermark. Check the watermark carefully. It should be again embedded in the paper and not a light gray print. The watermark is created by thinning out the paper. Your notes are UNC and from the photo the watermarks look real. I have seen cases where the light gray print creates a fake watermark but then the counterfeiters usually wear the note down so it does not look like a print.

Thank you for your response. Where is the watermark usually found for banknotes printed by the Central Bank?

These notes were printed by De La Rue. Several of the Central Bank of China and Farmers Bank of China issues printed by De La Rue during this period come with varying serial number types. This is most likely due to the bombing of the Bunhill Row factory during the Blitz; banknote printing had to be sub-contracted to other UK printing firms.