Nuremberg 'Rechen meister' Jeton of Hans Zwingel.
[These are also known as School pennies]
Obv; Rechenmeister sat at his counting table head turned right, jetons one side and counting grid the other. Rosette either side of table legs.
Rev; ABCDE FGHIK LMNOP QRSTV XYZZ within double banded square. 'O 3-foil O' to each side of the square.
Letter D is reversed, also the letter J did not exist in the alphabet at this time.
The extra Z is said to be Zwingelís signature