(Dan Tri) - Teachers believe that the explanation of the concept of "lunar calendar" in the History and Geography 6 textbook is incomplete and can easily lead to incorrect understanding.
The History and Geography 6 textbooks in all three current series (Creative Horizon, Kite, and Connecting Knowledge with Life) have the same definition of the concepts "solar calendar" and "lunar calendar".
Accordingly, the solar calendar is defined as "a calendar system calculated according to the cycle of the Earth's movement around the Sun". The lunar calendar is defined as "a calendar system calculated according to the cycle of the Moon's movement around the Earth".
According to Ms. NTTB, a geography teacher in Hanoi, the above definition of the lunar calendar is incomplete and can cause misunderstandings about the lunar calendar currently used in Vietnam as well as many other countries.
Explanation of lunar and solar calendars in History and Geography textbook 6, book Connecting knowledge with life (Screenshot).
"Many Vietnamese people think that the lunar calendar used by Vietnamese or Chinese people is a calendar based purely on the cycle of the moon's movement. Meanwhile, the lunar calendar in our country is actually a lunisolar calendar.
Crops and solar terms in our country are calculated based on the combination of yin and yang. Many experts have analyzed this," Ms. B. stated her opinion.
The structure of the lesson "Time in history" in the History and Geography Textbook 6 includes the first part explaining the concept of lunar calendar and solar calendar, the second part requires students to apply it in practice.
According to Ms. B., at this stage of application, if teachers do not expand beyond the textbook and explain clearly to students about the lunar calendar in Vietnam, students will apply it incorrectly.
"For example, in the book Canh Dieu, the application section has the question "What calendar is Vietnamese Lunar New Year based on?". If students only learn the general definition above about the lunar calendar and the solar calendar, they will answer "lunar calendar". Of course, this is a wrong answer," Ms. B. commented.
Part of applying the concept of lunar and solar calendars in the History and Geography Textbook 6, Canh Dieu book (Screenshot).
From there, Ms. B believes that if today's students want to understand correctly, textbooks must explain more fully. In addition to the general definition of the lunar calendar, it is necessary to explain the lunar calendar in Vietnam in particular," Ms. B stated her opinion.
Responding to Dan Tri reporter, representative of Information - Documentation Center, Vietnam Academy of Science and Technology, said that because the book only defines the solar calendar and lunar calendar in general, the concept stated in the book is accurate and complete.
"The concepts of "lunar calendar" and "solar calendar" in textbooks have ensured scientific accuracy and are easy to understand for students," the response document of the Information and Documentation Center stated.
Not sharing the same opinion, Master Tran Tien Binh, a calendar researcher and author of the book "Vietnamese Calendar of the 20th and 21st centuries", commented: "Writing as in the textbook above is clearly incomplete because it makes students misunderstand that the lunar calendar used in our country is a purely lunar calendar, only following the lunar cycle".
According to Mr. Binh, the lunar calendar in Vietnam should be correctly called the lunisolar calendar because it follows both the lunar cycle and the movement of the earth around the sun.
"The lunar calendar is abbreviated according to habit in Vietnam, the first day of the month is called No Moon Day or Soc Day. Soc Day is when the earth - moon - sun are in a straight line in the above order. The moon turns its dark side towards the earth, so we often say "As dark as the night of the 30th".
Calculating consecutive Soc points will give lunar months, which is a calendar based on the moon's phases.
But to suit the weather and climate, our calendar also associates these lunar months with 24 solar terms such as Lich Xuan, Xuan Phan, Coc Vu, Ha Chi, Tieu Man, Dai Han...
Each solar term above corresponds to a certain position of the earth around the sun, for example, Spring Equinox corresponds to the angle 0⁰, Qingming corresponds to the angle 15⁰, Coc Vu corresponds to the angle 30⁰, Kinh Trap corresponds to the angle 345⁰.
When comparing the lunar months with the solar terms above, specifically the Middle Solar Term, we can insert an extra intercalary month. Normally, the lunar year has only 12 lunar months, while the leap year has 13 lunar months. This helps to overcome the difference in length between the 12 lunar months - which are only 354 days long - and the solar year, which is longer than 365 days.
Because of the difference of about 11 days between the lunar year and the solar calendar, every few years we see a leap month appear in the lunar calendar.
For example, this year At Ty has a leap month of June," Mr. Binh analyzed.
The author of the book "Vietnamese Calendar 20th-21st Century" added that, in addition to the East Asian lunisolar calendar currently used in Vietnam, China, Korea..., there are also lunisolar calendars in other places such as the Jewish calendar and the Hindu calendar.
The purely lunar calendar that only follows the moon phase is the Islamic calendar. Accordingly, the first day of 2025 according to the Islamic calendar falls around July 8 or 9 of the Gregorian calendar.
"In our country, we still call it the lunar calendar, Lunar New Year. But when teaching students, we need to state it fully and accurately," Mr. Binh stated his opinion.
Source: https://dantri.com.vn/giao-duc/giao-vien-noi-sgk-dinh-nghia-khong-day-du-ve-am-lich-chuyen-gia-noi-gi-20250115114801771.htm
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