The following is from Wikipedia:

The folk origins of the mazurek are two other Polish musical forms—the slow kujawiak, and the fast oberek. The mazurek is always found to have either a triplet, trill, dotted eighth note (quaver) pair, or an ordinary eighth note pair before two quarter notes (crotchets). In the 19th century, the dance became popular in ballrooms in the rest of Europe. The Polish national anthem has a mazurek rhythm but is too slow to be considered a mazurek. There are many Polish editions of the mazurek but the most notable one is the mazurka.

In Polish, this musical form is called “mazurek“—a word derived from “mazur,” which up to the nineteenth century denoted an inhabitant of Poland’s Mazovia region, and which also became the root for “Masuria.” In Polish, “mazurka” is actually the genitive and accusative cases of “mazurek.”

The player in the first example is playing a chromatic button accordion made by Petosa, which is based in Seattle.

I like this simple and beautiful arrangement. The instrument looks like a  triple row diatonic button accordion, but it has an unusual bass setup with three rows on the bass side instead of two.

Here’s one that features two squeeze-boxes.

Finally, here’s a mazurka played on an Anglo Concertina: