Variant Hán characters (hereinafter referred to as variants) are a common phenomenon in various types of Hán-Nôm cultural materials, including Confucian documents. This article studies the variants in Confucian works through the case of the book Hồ thượng thư gia lễ/胡尚書家禮/Family rituals by Minister Hồ (printed in 1739). The author chooses this text because of the following factors: First, the content of this work, which might be described as Confucian in nature, is about Confucian rituals; Second, the text printed in 1739 is associated with clearly identified dates of production and chief commissioner, so variants found in this text have historical value; Third, this is a printed text, so its variants must have attained a degree of common usage. On that basis, the objectives of this article are: First, to provide statistics on variants, to classify their structures and to analyze some variation rules of this type of characters; Second, to provide preliminary comments (relying upon the above-mentioned data and analysis) on the flexible use of Hán characters by Vietnamese Confucian scholars in the 18th century.