A handshake is one of the most common ways to greet others, but US President Donald Trump's unusual method has been put under the microscope lately.

    Much like an arm wrestler in a match, the recently-elected leader has a habit of yanking (猛拉) people's hands toward himself during handshakes. And while a typical handshake is only brief, the one between him and Japanese Prime Minister Shinzo Abe on Feb 10 lasted a full 19 seconds.

    Simply having a strong hand is not the explanation here. According to Darren Stanton, a body language expert from the UK, while handshakes are usually an exchange of kindness, Trump uses his as a way to show power and control, regardless of how uncomfortable it makes people. “It is as if to say, 'Hey, I'm in charge, don't mess with me,' ” Stanton told The Independent.

    Apart from Trump's “yank-shake”, there are other ways people display power with their hands. At business talks or political meetings, for example, some people may rotate (旋转) their wrists during handshakes so that their hand ends up on top instead of underneath. Some may squeeze so hard that it leaves the other person's hand in pain.

    According to Stanton, by pulling people into his personal space, Trump is also testing whether they are willing to cooperate with him. “For example, if someone was resistant to being yanked towards him and stood their ground, he would know that he has work to do with them before he got what he wanted,” Stanton told Express.

    This is probably why on Feb 13 when Canadian Prime Minister Justin Trudeau visited the White House, all eyes were on how he was going to handle Trump's handshake. Fortunately, Trudeau managed to avoid the embarrassment by grabbing Trump's shoulder to stop himself being pulled in. Afterward, some Twitter users wrote that this proved Trudeau's strong leadership, with one even calling the moment “one of Canada's greatest victories”.

    Vice magazine summed up the exchange between the two leaders as: “... no regular handshake. This was the first shot in a bloodless war.”