Since Christian missionaries still could not get a copy of the Kaifeng Holy Books, the next best thing was to send a Catholic scholar who knew Hebrew to study the texts onsite. This mission fell onto the shoulders of the French Jesuit Jean Domenge (1666–1735).

Father Domenge was linguistically gifted. He learned Hebrew in the early days of his Jesuit education. During his years in China, he became fluent in both Mandarin and Manchurian, the language of the ruling Qing royals. His mastery of Chinese allowed him to cultivate a closer relationship with the members of the Jewish congregation; he, therefore, could gain more direct access to the information and material he needed. Likewise, his fluency in Hebrew allowed him to interact with the manuscripts of the Kaifeng Jewish library; this facilitated a more intimate relationship with the texts and allowed him to form opinions on the Sinicization of Hebrew vowels and consonants.

Father Domenge copied a colophon from a Pentateuch, later identified by scholars as Judeo-Persian and evidence for the KaifengJews’ Persian origins.

In two of Father Domenge’s letters, he commented that their local dialect heavily influenced the Hebrew pronunciation by the Kaifeng Jews.

In one of the letters, he wrote, "They have lost the true pronunciation of Hebrew, in fact, they pronounce Hebrew in a Chinese manner…. All that I have been able to understand of their way of reading is that, having lost the knowledge and pronunciation of accents, they have substituted in its place the four tones of Mandarin of the Chinese."

In another letter, Father Domenge stated, “But just as much as their script and their Alphabet is similar to that of the European Jews, so is their pronunciation different. Since they … have been born Chinese and the Chinese have no b, d, e, r, nor several other sounds of our alphabet, it follows that they pronounce p for b, t ford, ié for e, ou for u, etc.”

Father Domenge met with the Jews on several occasions and attended their services in the synagogue at least once. The synagogue's architecture was similar to that of a Confucian shrine, and it was relatively spacious. The synagogue measured 60x40 feet. The entire compound measured 400x150 feet. The courtyard had three layers of the entrance.

The main gate faced east and was guarded by a pair of stone lions on each side.

The arch that framed the gate was 3.8 meters tall, with a horizontal plaque on the top with words from Emperor Kang-xi (康熙大帝, reign 1661–1722), Worship Heaven Bless Country (敬天祝国). The word Heaven here, to the Kaifeng Jews, means the One God that they serve. The worship stand faced the west, in the direction of Jerusalem (耶路撒冷).

Inside the synagogue, there was a Hall of Ancestors (祖殿) where ancestral worship was conducted in a manner similar to the local Confucians, except there were no images in the Hall, and no pork was used as a sacrifice.

The second gate led to the synagogue itself; directly inside stood the stone inscriptions of 1489/1512 and 1663.

On the sides of the Main Hall were the Lecture Hall (讲经堂), kitchen, and Founder of the Religion Hall, as well as the Holy Patriarch Hall where figures including Abraham (阿无罗汉), Esau (厄撒乌), Jacob (雅各), Moses (摩西), and Ezra (蔼子剌) were venerated. None of these halls had any images on the nameplates.

On the western wall were the carvings of the Ten Commandments (十诫). There was a giant Ark in the alcove, with curtains draped in front of it; before the Ark was a table on which stood a tripartite archway and on this archway was an inscription in Hebrew: Blessed be the LORD, the God of gods, and the Lord of lords, the great, the mighty and the terrible God. Here, there were thirteen tabernacles, each covered by its own curtain, inside of which were the thirteen rolls of Pentateuch (摩西五书). In the middle was the oldest and most valuable one, rescued from the flood of 1642 and dedicated to Moses. The other twelve copies were dedicated to the Twelve Tribes of Israel (以色列的十二支部落).

All of the community’s Scripture Rolls (经卷) were stored in the synagogue; lay individuals were not allowed to keep any Hebrew manuscripts in their houses.

Having failed at his attempts to acquire the Holy Books, Father Domenge approached, in private, a Jew by the name of Gao Ting who was a junior official in the observatory. Gao Ting was not a dedicated Jew and did not practise any aspects of the religion since his father's death. However, he was bequeathed a very well written Torah by his uncle. Gao deposited it several years prior in the synagogue, as was common practice for Jewish community members trying to distance themselves from religious obligation.

These books were now “watched over by a concierge, whom they call T’ang-chia in Chinese, who, however ignorant he may be, is honoured with the title of Man-la (瞒喇), or Doctor, and would be dismissed without mercy if anything in the temple, especially the books, should get lost because of his fault.” When Gao Ting approached T’ang-chia, his request was rejected. He was lectured, "willing to sell the Bible to a European who eats the black beast (pig), besides the infamy that there is in selling the Torah, this being, according to them, the same thing as to sell the Lord."

Father Domenge tried again to circumvent the wishes of the kehillah's elders, this time via a layman who went by the name Ai Wen. Ai, who had deposited four manuscripts at the synagogue, agreed to reclaim the books and sell them to Father Domenge; however, he was “caught in the act one festival day as he was carrying them off, he was compelled to leave them behind, and was sent away with a rebuke. He has not been permitted to see me since, and to give me hope of obtaining them sooner or later.”

Before the Kehilla lost faith in him, Father Domenge was allowed access to the manuscripts in the synagogue. He copied a Judeo-Persian colophon to the Pentateuch and made a list of the available books and examined the texts in great detail.

Father Domenge concluded that the Kaifeng Torah was the same as the version in the West. He discovered numerous spelling errors in the former and certain variations in scribal style, but in no case was the content of the text notably different. He concluded that the Talmudists did not tamper with the Biblical texts.

The Christian community in Europe was not satisfied by this conclusion, likely because they did not see the Kaifeng Torah themselves.

By the 19th century, the Kaifeng Jewish community declined to a state where they sold their Torah scrolls. It became clear that the Chinese Torah Scroll was no different from the European Torah Scroll and that Father's Domenge’s conclusion from centuries ago was correct.

In a letter dated 1721, the longest of his six letters, Father Domenge sent back to Father Etienne Souciet in Europe several detailed sketches of the synagogue; three were particularly notable. The first offered a general view of the synagogue compound. The second depicted the synagogue's interior, and the third showed three Kaifeng Jews reading the Torah during a religious service.

Father Joseph Brucker subsequently tidied up the drawings and “improved” the Torah Reading sketch by putting shoes on the bare feet of the three men; he also beautified the faces and noses of two of them. These sketches are now the only surviving representations of what the Kaifeng synagogue looks like.