Free Race Against Time by Piers Anthony

I believe. But Christ was in one of the barbarian Western states. The Roman? Or was that Muhammad?"
    "No. Muhammad was about six hundred years later, in Arabia." John paused, just now remembering an obscure bit of lore he had picked up from his historical studies. The Moslems started their dating with Muhammad! From the time he left Mecca, rather than his actual birth. John had been required to memorize that date: A.D. 622. Now he was thankful for that chore. That meant that the date of Ala's enclave was six hundred years later than he had supposed. Between A.D. 1500 and 1600.
    "So this must be about seven hundred fifty by the Christian scale," the man said. "Seven hundred forty, perhaps."
    "And your 'Middle Kingdom' means China? Not ancient Egypt?"
    "Naturally. Many cultures had 'middle kingdoms,' but the T'ang dynasty is the most civilized place and time in all earth's history," the man said with a certain pride. "Pre-Standard, of course."
    "Of course." So this was what China was like twelve hundred years ago. T'ang dynasty—John remembered it only faintly from his classroom lessons. Famous for painting, or something. "What do you do here?"
    "I'm a civil-service examiner. I administer the hsiu ts'ai and send the results in to the emperor every year, and every three years the chu jen. Those are rough tests, too. Most applicants are eliminated by the hsiu, and only one in fifteen passes the chu. Of course it isn't real, except for him."
    "You actually tested the purebreds?"
    "The true Mongolian, yes. Yao Pei, that is. The girl isn't eligible. I supervise all the tests. The records have to be genuine, you see, just in case. Keeps me busy, but I rather like it. It's a meaningful task, in its quirky way, and that's important. A man needs meaning, you know?"
    "Yes." Did this mean there was no meaning in conventional Standard existence? Very interesting.
    As they talked, John was being fitted with full Chinese apparel. "What's your job to be, in your own enclave?" the man inquired.
    "Well, I haven't started yet, of course," John said, scrambling mentally for a suitable answer. "But I'm supposed to be a—an auto mechanic. Transferred in for the bus station." That should hold him, since there were no cars or buses—or, indeed, any machines at all—in ancient China. No internal combustion engines, anyway, and probably very few in the Standards' home territory, either. Not when they had such advanced equipment as the flying taxi-spheres. So chances were that this civil-service examiner wouldn't know enough to ask penetrating questions.
    He was right. The man concealed his ignorance by fetching a jar of yellow paste. John hoped it would go on over the brown paste he had used not so long ago. "The real one—did he pass the tests?"
    "Yes, strangely enough. Yao Pei is astonishingly knowledgeable, considering that he's had what we assume is a typical period schooling. I sealed him into his cell myself, so I know he spent the full three days as prescribed, without food. To him it was real, you see. I gave him obscure topics from the literature of Confucius, but he composed fully satisfactory poems—almost perfect styling. Amazing."
    "You sealed him into a cell? For a literature test?" John didn't have to pretend astonishment. Meanwhile he studied himself in the bronze mirror. He looked Chinese.
    "That's the way it's done. In the real Middle Kingdom the aspirants sometimes died from the strain. But it was the only route to status and the official posts. So we duplicate it faithfully. I myself feel that is has its merits, for you can be sure that no weak man passes. But of course it also leads to intellectual arrogance and narrowness of thought. I am certain that this was the root of the downfall of T'ang and all subsequent Middle Kingdoms. In fact"—the man brought himself up short. "I'm waxing philosophical again! Must curb that."
    John had been rather interested in that philosophy, as it seemed to apply to a certain degree to his own