Actually, I had to look this guy up, and it is a ‘concertina’. I have no idea what the difference is, but...I’m gonna find out...:)
This is a little snippet I found:
Aleksandr Hrustevich, Internet Accordion Star
On the Internet can you become a star overnight; just ask Ukranian accordionist Aleksandr Hrustevich. Late last week, this video of Hrustevich performing the third movement of “Summer” from Vivaldi’s “Four Seasons” swept across the Internet faster than his fingers across his bayan (Russian chromatic button accordion). From NPR to Digg, viewers raved about his performance, mostly along the lines of “Wow, I never knew an accordion could sound like this!” Indeed it can.
Its been up about a year now. Sounds like an orchestra.
Concertina has buttons.
Accordian has buttons on one side and a key board like a piano on the other side.