Chinese President Hu Jintao has met Barack Obama several times before, but never during a state visit to the United States. He will be the first Chinese leader treated to a White House dinner in 13 years.
Over four days the two men are expected to tackle some exceptionally thorny issues, and many US commentators are wondering how a Nobel peace prize winner will be able to skirt around the human rights issues Beijing refuses to recognise.
There were plenty of supporters out to welcome the Chinese leader, but it is the opponents of the Communist regime who are likely to get the most press coverage.
The past year has been one of the tensest between the two powers in decades, and Obama has spoken of a desire to “reset” foreign policy and economic relations. Human rights campaigners hope that their priorities will not be ignored.