Zhang Xinwang, a moon-faced Chinese man with a spiky beard, calls himself “Moishe.”

　　张新旺（音），这个圆脸的中国男子留着长而硬的连鬓胡子，他称自己是“摩西”。

　　“So do you think I look Jewish?” he asks.

　　“你认为我长得像犹太人吗？”张新旺问道。

　　For much of the past millennium, Jews in Kaifeng -- descendants of merchants who arrived here from Persia -- have been struggling with an existential question: What does it mean to be Jewish? Bob Davis/The Wall Street Journal

　　张新旺称自己是“摩西”。 过去一千年的大部分时间里，开封的犹太人一直想搞清楚一个事关这一人群存在的问题：何谓犹太人？中国这支犹太人是当年从波斯来华的犹太商人的后代。

　　The handful of Kaifengers who go to Israel are sometimes floored to discover they need to go through a rabbi-certified conversion to be accepted as Jews, while the ones staying home squabble over which of them are really Jewish.

　　那些为数不多前往以色列的开封犹太人有时会沮丧地发现，他们需要经过由犹太教牧师认证的宗教改宗，才能被接纳为犹太人，而那些留在开封的中国犹太人则在为他们谁才是真正的犹太人争吵不休。

　　The question has surprising consequences in this dusty walled city in central China. According to the Chinese government, there are no Kaifeng Jews because there are no Chinese Jews. Judaism isn't one of China's five official religions and Jews aren't designated as one of the country's 55 official minorities. Orthodox Jews have a similar view, though for different reasons. Kaifeng Jews trace their heritage through their father, as Chinese traditionally do, while Orthodox Jews define Judaism as passing through the mother.

　　在开封这个中国中部尘土飞扬的城市，这一问题产生了令人惊讶的后果。中国政府认为，并不存在开封犹太人，因为根本就没有中国犹太人。犹太教不是中国获官方认可的五大宗教之一，犹太人也不是中国被官方承认的55个少数一民族之。正统犹太人持与中国政府相同的看法，虽然其理由并不相同。像中国人传统上那样，开封犹太人是通过父系追踪其血缘传承的，而正统犹太人则是通过母系来确定其犹太血缘。

　　“They may stem from Jewish ancestry, but they aren't Jewish,” says Rabbi Shimon Freundlich, who runs the orthodox Chabad House in Beijing. “There hasn't been a Jewish community in Kaifeng in 400 years.”

　　在北京经营着正统犹太人中心的犹太教牧师希蒙•弗罗因德利希（Shimon Freundlich）说，开封这些人可能有犹太祖先，但他们不是犹太人，开封400年来一直不存在犹太人社区。

　　Except there is one, some say, though it's divided and diminished. Somewhere between 500 and 1,000 people in the city say they are descendants of Kaifeng Jews and cling to at least some Jewish traditions. A canvas poster at No. 21 Teaching the Torah Lane announces the street as the site of a synagogue that was destroyed in an 1860 flood and never rebuilt. Inside a tiny courtyard house, “Esther” Guo Yan sells knick-knacks with Jewish stars.

　　但有人说开封存在犹太人社区，虽然它是分裂和被贬低的。这个城市大约有500到1,000人称自己是开封犹太人的后代，他们至少还坚持着一些犹太人的传统。开封南教经胡同21号张贴的一幅帆布海报说，这里是一座犹太教教堂的原址，这座教堂1860年被洪水摧毁，此后再也未能重建。在这条胡同的一个小院里，教名为“埃丝特”（Esther）的郭燕（音）在卖有犹太星标记的小装饰品。

　　When tourists stop by, she quizzes them on Jewish ceremonies, like what prayers to say when lighting Sabbath candles. She says she hasn't yet managed to fast a full day on Yom Kippur, though she is trying. As the granddaughter of a Kaifeng Jew, she says the Orthodox standard on Judaism is unfair: “We read the Torah with Eastern thoughts.”

　　当游客们驻足观看时，她会考问他们一些有关犹太礼仪的小问题，比如祈祷者在点燃安息日蜡烛时应说些什么。她说自己还没能做到在犹太人赎罪日全天禁食，不过正在尝试这样做。作为一名开封犹太人的孙女，郭燕说犹太教的正统标准是不公平的。她说，我用东方思维读犹太教经典。

　　The first Jewish merchants arrived when Kaifeng was in its heyday as the Song dynasty capital. They married the local women and rose to become mandarins and military officials. Over the centuries they blended in and were forgotten by the world until 1605, when a Jewish scholar from Kaifeng, Ai Tien, met Jesuit missionary Matteo Ricci in Beijing. The missionary then spread the news that Jews had been living in China for centuries.

　　Bob Davis/The Wall Street Journal开封最后一个犹太教堂1860年被洪水摧毁，现在这里是一条四合院的胡同（开封南教经胡同）。当犹太商人最初抵达开封时，作为北宋首都的这座城市正处于自己的鼎盛期。这些犹太人与当地妇女通婚，其后代中有人做了文职官员和军官。在此后的几个世纪里，这一人群与中国当地人逐渐融合并被世界所遗忘，这种局面直到1605年才出现改观，当时来自开封的一名犹太学者艾田在北京会晤了耶稣会传教士利玛窦（Matteo Ricci ）。利玛窦后来将犹太人已经在中国生活了好几百年的消息传播了出去。

　　The Kaifeng Jewish population is thought to have peaked at around 5,000 members, but by the early 1900s none could read Hebrew and the community's Torah scrolls were sold to collectors. Jews were called “the Muslims with the blue caps,” referring to the color of the yarmulkes some still wore.

　　据说在鼎盛时期，开封犹太人的数量达到过5,000人左右，但到20世纪初时他们已经没有人懂希伯来文，社区的犹太教经典卷轴也卖给了收藏者。由于有的开封犹太人仍戴着犹太男子所特有的蓝色圆顶小帽，因此他们被称为“蓝帽回回”。

　　“In our family, we didn't eat pork,” says Nina Wang, a 24-year-old Kaifeng native who now lives in Israel and underwent orthodox Jewish conversion. The family had menorahs and Sabbath cups, she said, “but we didn't know what to do with those things.”

　　24岁的Nina Wang是土生土长的开封人，现在住在以色列，已经完成了皈依犹太教的正统仪式。她说，我们家不吃猪肉；家里有犹太教烛台和圣杯，但我们不知道这些东西有什么用。

　　When thousands of European Jews settled in Shanghai in the 1930s and 1940s to escape the Holocaust, a few Kaifengers went there to study. But the Shanghai Jews were focused on aiding those persecuted in Europe.

　　20世纪30年代和40年代，数以千计的欧洲犹太人为逃避大屠杀在上海定居时，一些开封人前往上海学习。但上海犹太人主要是帮助那些在欧洲遭到迫害的人。

　　After the Communists took over in 1949, Mao Zedong and Deng Xiaoping fretted that Kaifeng Jews might be subversive. In a 1953 document, they wrote that the Kaifeng Jews were “disclosing secrets to the overseas communities and causing trouble.” Even so, Kaifeng Jews say they weren't singled out for discrimination. Ms. Guo says that her friends used to tease her, saying she must be smart and good at making money -- common Chinese stereotypes of Jews.

　　共产党1949年掌权后，毛泽东和邓小平担心开封犹太人可能成为颠覆分子。他们在1953年的一份文件里写道，开封犹太人在“向海外团体透露秘密并制造麻烦”。尽管如此，开封犹太人说他们并没有遭到歧视对待。郭燕说她的朋友以前总是取笑她，说她肯定既聪明又会赚钱，这是普通中国人眼中的犹太人典型形象。

　　As China opened again to foreigners in the 1980s, Jewish tourists, Christian missionaries and foreign academics made their way to Kaifeng, each doling out different advice.

　　20世纪80年代中国再次对外开放时，犹太游客、基督教传教士和外国学者纷纷来到开封，他们给出了各种各样的建议。

　　These days, many in Kaifeng turn to Timothy Lerner, who was born Jewish but believes in Christ as the Messiah, to learn Hebrew and Jewish customs. Mr. Lerner says he doesn't try to convince anyone to follow his religious beliefs. He says he set up the 'Kaifeng Israel School' to help Kaifeng Jews “learn the Jewish lifestyle” and move to Israel, which about a dozen did.

　　如今，许多开封人都向勒纳（Timothy Lerner）学习希伯来文和犹太习俗。勒纳生来是犹太人，但相信耶稣是帮助犹太人复国的救世主。勒纳说他不会试图劝任何人追随他的宗教信仰。他说自己创建“开封以色列学校”是为了帮助开封犹太人“学习犹太人的生活方式”，并且帮他们移居以色列。约有12人已经搬到了以色列。

　　Others in the Jewish community are suspicious. Shi Lei, one of the first Kaifeng Jews to study in Israel, blames Mr. Lerner for “creating factions” with his school, though Mr. Lerner says Mr. Shi misunderstands his efforts.

　　开封犹太社区的其他人对勒纳的做法持怀疑态度。石磊（音）是第一批到以色列学习的开封犹太人之一。他指责勒纳利用自己的学校“制造摩擦”，但勒纳说石磊误解了他的努力。

　　Today, Kaifeng Jews tread with caution. Jewish descendants rarely meet in groups of 10 -- the number required by Jewish law for a religious service -- for fear it will be seen as a political gathering. Passover is celebrated as a restaurant meal, not as a religious gathering, though some pass out matzos sent from Hong Kong.

　　如今，开封犹太人如履薄冰。犹太教律法要求参加宗教仪式者最少须有十人，但开封犹太后裔很少这样做，因为害怕被视为政治集会。他们将庆祝逾越节（Passover）的活动称之为聚餐，而不是宗教活动，不过有人会在聚会上散发从香港送来的无酵饼。

　　Some of the city's notables (none of whom are Jewish) are looking to boost tourism by rebuilding the Kaifeng synagogue. “You could have tourists stay a night with local Jewish descendants,” says Su Linzhong, a management professor at Kaifeng University. “They are so emotional about their grandparents.”

　　开封市有些名人希望通过重建开封的犹太教堂来提振旅游业。他们都不是犹太人。开封大学管理学教授苏林忠说，可以让游客在开封犹太人后裔的家里住上一晚；他们对自己的祖辈有很深的情感。