Peter III (1762)

As noted above, when Peter III ascended to the throne, he changed the monetary standard and struck many of his four kopeck and ten kopeck pieces over two and five kopeck pieces of Elizabeth, respectively. As far as I know, these were the only coins he used as planchets, so identifying the undertype is pro forma. The most obvious traces of the two kopeck undertype are the date (rarely seen), the wreath from the obverse, Elizabeth's monogram from the obverse, and the horse and rider from the reverse. The following two kopeck example shows the "9" from the 1759 date and major remnants of both the wreath and the monogram, making the undertype very easy to verify.

This example is verifiable as to undertype by traces of the monogram.

The following ten kopeck piece shows a substantial portion of the wreath from the Elizabeth five kopeck undertype.

The undertype on this 1762 ten kopecks is verifiable by the traces of Elizabeth's monogram.

Paul I (1797-1801)

As I noted at the outset of this article, the overstriking of previous rulers' coins continued under Paul I (1797-1801), and identification of those undertypes is simple, being confined to the 1796 "Cipher" series. I invite the reader to consult that article to conclude your education of copper overstrikes of 18th century Russia. As far as I know, no rulers after Paul struck coins over the coinage of previous rulers.

To read the earlier E-Sylum articles, see:
THE 1797 RECOINING PROGRAM OF CZAR PAUL I OF RUSSIA(www.coinbooks.org/esylum_v19n08a30.html)
IDENTIFYING OVERSTRUCK RUSSIAN COPPER UNDERTYPES: PART I(www.coinbooks.org/esylum_v19n48a22.html)
IDENTIFYING OVERSTRUCK RUSSIAN COPPER UNDERTYPES: PART II(www.coinbooks.org/esylum_v19n49a22.html)