In 1999, we invited Professor Cui Xiliang of Beijing Language and Culture University to compile the book The Explanations of Keys to HSK Grammatical Section in order to help students get to know the grammatical items in HSK and make them understand what’s right and why. This is the Japanese-annotated version of the book. Based on A Graded Syllabus for HSK Grading Criteria and Grammar and the Outline of HSK Test(elementary and intermediate levels) formulated by the HSK Center of the State Committee for the Chinese Proficiency Test, the book absorbs some latest results of researches on modern Chinese grammar, simulates the standardized test paper of HSK, takes in grammatical test questions suitable to examinees at the elementary and intermediate levels and gives simple explanations on the grammar points of the questions. The book is suitable for self-teaching under the guidance of Chinese language teachers and can also be used as a textbook for tutorial classes before the test. The other lead author of the book is Wang Xiaoling of BLCU and other compilers include Yao Hongchang, Zhou Rong and Du Xintian of BLCU. The explanation section is translated by Molinaka Nosa, a PH.D. candidate in Ochanomizu University and a senior visiting student in BLCU.