What Greek letter is j

Greek Learning Greek
1

In Cunliffe, under the entry [size=150]πεζός[/size] is a Greek letter that is just like our j.
What is this letter?

2

Your j, that is, what English uses a y for. (The Dutch j is like Eng. y, yes?)

3

Ja. (yes)
It is a Greek letter is it not? I’m kind of surprised that it has a dot on it, but it is written as part of a Greek word.

4

C. is using the Latinate j to indicate a sound we know Greek once had, but which had dropped out by the time we come across archaic Greek. It left chaos in its wake (i.e., lots of changes of the dj > zd sort).