The US Open is the second of the year's four Majors and is staged annually in mid-June by the United States Golf Association.

The organisers traditionally make it tough to post low numbers, setting up the championship courses to provide a severe test. Accurate driving is usually demanded, with punishing rough.

High scoring is normal don't expect the guys at the USGA to have sleepless nights if the winner fails to beat par.

Oakmont Country Club in the Pittsburgh suburbs has staged most US Opens since the tournament was inaugurated in 1895 with eight, followed by Baltusrol in Springfield, New Jersey, with seven.

Unusually in a society that seems to demand instant gratification, the US Open does not have a sudden-death play-off in the event of a tie after four rounds. Instead, the players return the next day and contest another 18 holes, with sudden death applying only after that.

This last happened in 2008, when Tiger Woods was hampered by an injured leg but kept going for five days and finally shook off Rocco Mediate at the first extra hole. It was only the third such finish in US Open history.

A big field of over 150 players compete in the tournament but entries can easily top 8,000, and with about half the places taken up by exempt categories, qualifying events are staged from early in May all over America and in both Europe and Japan. In 2008, the youngest entrant was 12 and the eldest 79.

It has been notoriously difficult for non-Americans to win the US Open in modern times, but that appears to have changed since the turn of the millennium.