Watch List notes:

(x) Central Bank of Yemen, a group of progressive proofs from the 1973 issue, comprising 1 rials (2), 5 rials (2), 10 rials, (2), 20 rials (2), each showing the various layers of printing on the obverse and reverse(Pick 11-14, TBB B101-104 for type), about uncirculated to uncirculated (8).

Estimate: £500 - £600