Jeopardy under a ginkgo tree

I had my camera lens a few inches from a ginkgo leaf that was resting on a rock when I noticed a face approaching from the left. It was getting closer so I glanced away from my prey for a second to see what the looming face belonged to. It belonged to an old man who was asking me if I was Japanese. He was already short but his stooped posture made him even shorter. He was wearing a baggy sweat suit he was holding up with an outsized hand. He must have been 80-90 years old and he looked like he had been beaten for about 70 of those years. Where I'm from they'd say he looked as if he'd been ridden hard and put up wet.

"Do you know who our prime minister is?" he asked in English. I passed that test so he asked me if I knew the name of the ruling party in Japan. Passed that one too so he pressed on with harder and harder questions. When he failed to stump me he switched gears and told me to ask him if he knew who any US presidents were. "Do you know any US presidents?" I repeated dutifully. Then, bent over so far I couldn't see his face he proceeded to name every single US president, in order, starting from Washington and ending with Obama. Good grief I thought. I couldn't do that. Not one in a thousand Americans could do that. I asked him how he came to know that and why he spoke pretty good English. "Oh, it's nothin' the top of his head said to me as he shuffled away without looking back.