May 31 is Memorial Day in the US, something that as a veteran I still think of as a time for mattresses and auto sales. But there are other veterans besides those in the US who are equally as battle-scarred. I have met a couple – Vietnam War veterans from China and Thailand.

One was the second Asian Vietnam vet I met while living in Asia. Not a Vietnamese vet from the US-Vietnam conflict, but a Thai man who lived across the way from my office in the residential soi where I worked.

He briefly scared the bejeebus outta me the first time I encountered him. I was leaving work and I could hear him before I saw him, striding a bit awkwardly around a corner. He had an exaggerated missing-teeth grin, James Dean shades and was dressed neatly; he was in his late-50s/early-60s and was talking loudly to no one in particular in Thai.

Startled, I did a sort of half-wai, half-salute to show I meant no harm. He snapped back a real salute, military-style, grinning a bit, before resuming his dialog with his invisible pals and going through a gate where one of the loudest most obnoxious dogs in Southeast Asia joyfully greeted him.

I privately dubbed him "the crazy walking man" and about a week later I noticed him again,walking far from his home several times, still talking.

"What's with our crazy neighbor? The guy who talks to himself and walks everywhere," I asked one of our Thai employees, a 20-something woman named Nam.

"He has no arms," she said.

"What? I saw them," I said.

"Not real," she replied. "Look more when you see him again." I realized that, yes, they had looked a bit stiff but I'd been concentrating on his face so much I'd barely noted the arms. Nam explained he'd lost them in an explosion "a long time ago."

"Where? What happened?" I asked. "Vietnam, I think. Maybe Laos," she said. "He was a soldier." She went on to say he'd served with a "special army for the Queen" and had been mutilated by what must have been a Vietcong or Pathet Lao mine. I Googled around and found, yes, Thai soldiers - including an elite group called "The Queen's Cobras" –had fought in Vietnam and covertly in Laos.

"I ask him before if he wants help," she said. "I can ride my motorbike and get things for him but he say, 'Thank you. No, I am a soldier! I do it myself. A soldier does it himself.'"

I do a real salute when I see him these days. He snaps one back with his brown, plastic arm, grins and keeps walking and talking on his endless reconnaissance.

The other vet was a Chinese "black taxi" (gypsy cab) driver, one of about eight or so that always parked their cars outside my Shenzhen apartment. He hadn't fought against the US, but against the Vietnamese in the short, nasty and obscure 1979 Sino-Vietnam border war that the Chinese don't talk much about, partly because they got their heads handed to them by the battle-tested Vietnamese who, after kicking US butt, had then gone into Cambodia and overthrown Pol Pot.

My friend C told me about "Mr Zhang" and later translated for me as he drove us to the Shenzhen border crossing on our way to Hong Kong. His wounds weren't visible but he was hurting. "I told him you were a soldier before," C said. "He asked me. ‘Vietnam?’ I said, ‘Korea.’ You didn't kill anyone, did you? No. Anyway, he wants to meet you anyway." I guess they don't have a lot of veteran's support groups in China and I was the next best thing.

I shrugged. "Sure," I said. "I knew a couple American soldiers who were in Vietnam. Chris's brother was one. He didn't kill anyone either but his friend died falling off a truck in Saigon. His name is on a plaque of dead soldiers at my university."

Mr Zhang had some horrors to recount. He'd served with a Guangdong province unit in the People's Liberation Army and until they'd been mobilized with what he called "50-year old maps and old guns from when China liberated Korea from the US" he had had little idea of where or what Vietnam was.

What he told me sounded depressingly familiar. After declaring "victory" when they captured a town called Lang Son, the Chinese retreated with a scorched earth policy.

"We burned everything," he said. "We did bad things to the people. Old people, children everyone." He sounded haunted and also oddly matter-of-fact when he described burying Vietnamese civilians up to their necks and torturing them for reasons he either couldn't articulate or C couldn't translate. I kept thinking of My Lai and mentioned it.

He never heard of it but said, "Americans, Chinese, it does not matter. All soldiers are animals sometimes." Then he changed the subject and asked if we knew any American women who wanted to marry a Chinese man. He wants to go to the US. His plan is to sell his late-model car and use the money to pay an American woman to marry him and get him into the country.

I thought about it and surprisingly no women came to mind who would want to marry a psychologically damaged Chinese Vietnam vet who drives a gypsy cab, even for money.

"I'll ask around," I said anyway. "But probably not. Tell him I hope he has better memories sometime soon, though."

That was the last time I saw Mr Zhang but I think of him now every time I salute my damaged neighbor. Two vets, two wars in one country neither understood. In Shenzhen Mr Zhang drives and dreams, and in Hua Hin the old Queen's Cobra walks and talks.