<P> In the original form, the dominant chord continued through the tenth bar; later on the V--IV--I--I "shuffle blues" pattern became standard in the third set of four bars: </P> <Dl> <Dd> <Table> <Tr> <Td> I </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> IV </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> V </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> </Table> Play (help info) </Dd> </Dl> <Dd> <Table> <Tr> <Td> I </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> IV </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> V </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> </Table> Play (help info) </Dd> <Table> <Tr> <Td> I </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> IV </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> V </Td> <Td> IV </Td> <Td> </Td> <Td> </Td> </Tr> </Table>

How many times is the twelve-bar blues form played