JapSin II, 17
Jihe yaofa 幾何要法.
Dictated by Ai Rulue 艾儒略 (Giulio Aleni) and transcribed by Qu Shigu 瞿式榖.
Four juan. Bamboo paper, two ce bound in one volume, European style. Published by the Catholic church of Fuzhou 閩中景教堂 (Fujian). No date of publication.

The middle of the title page bears the title in four large characters; on the right the author’s name is given 艾思及先生述 and on the left that of the publisher: 閩中景教堂藏板. On the verso of this folio the title of the book and the author’s name are given again, with the names of the censors: Gao Yizhi 高一志 (Alfonso Vagnone) and Deng Yuhan 鄧玉函 (Johann Schreck [Terrenz]). The imprimatur was given by Yang Manuo 陽瑪諾 (Manuel Dias Jr.), then Vice-Provincial.
There is a preface in four folios by Zheng Hongyou 鄭洪猷 of Liu’an 六安 (Anhui), dated Chongzhen 4 (1631).
The first folio of each juan gives the title of the book, the number of the juan, the names of the authors: 泰西艾儒略口述 | 海虞瞿式榖筆受 and of the proofreader, Ye Yifan 葉益蕃 of Fujian.
Each of the four juan has a table of contents (two, three, two and two folios). The main text of juan 1 consists of nineteen folios, juan 2 of nineteen folios, juan 3 of eight folios and juan 4 of ten folios.
In the middle of each folio the title of the book is given and the number of juan is given below the fish tail. Each half folio has nine columns, with nineteen characters in each column.
Pfister describes this book as: “Principes de géométrie” (p. 135, no. 22) and Couplet’s Catalogus as: “Praxes necessariae Geometricae” (p. 17). It deals with the line and the plane in geometry.
Qu Shigu was the eldest son of Qu Taisu 瞿太素, one of the first converts of Ricci. He was born in 1593 (Wanli 21) and baptized in 1607. In homage to Ricci he took the Christian name Matteo. In 1623 (Tianqi 3) he invited the missioners to Changshu 常熟, his native place, to start a mission there. We are told that through his efforts over 200 of his countrymen became Christians within a short period (cf. JWC 1:276–277; ECCP 1:199).

Cf. CJC, juan 44, ce 5, p. 576.
Source: Albert Chan, S.J., Chinese Books and Documents in the Jesuit Archives in Rome, pp. 297-298.

JapSin II, 18
Jihe yaofa 幾何要法.
Dictated by Ai Rulue 艾儒略 (Giulio Aleni) and transcribed by Qu Shigu 瞿式榖.
Four juan. Bamboo paper, two ce bound in one volume, European style. No date or place of publication.

The cover bears a label with the title and a Latin inscription: “Liber Primus | Geometricus | de lineis. | Liber Secundus de lineis | inscriptis et circumscriptis | circulo. Liber Tertius de Angulis | et Triangulis. | Liber Quartus de Potentia linearum. | a p. Julio Aleni, S.J.”

JapSin II, 18a
Jihe yaofa 幾何要法.
Dictated by Ai Rulue 艾儒略 (Giulio Aleni) and transcribed by Qu Shigu 瞿式榖.
Four juan. Bamboo paper, two ce bound in one volume, European style. No date or place of publication.

The cover bears a label with the title of the book and a Latin inscription: “Compendium geo | metriae | a p. Julio Aleni | S.J.”