The Petersburg accordion (also "Petrogradka" or "Peterburgska") is a Russian system 3-row diatonic button accordion. Its keyboard layout is similar to other 3-row diatonic accordions, but it designed to be played with the tonic on the draw of the bellows, and includes a greater number of chords. The body and bellows construction more closely resembles that of chemnitzer concertinas and bandoneons. Besides Russia, it has been adopted by folk musicians in other parts of the former USSR, especially Lithuania and Latvia.