There are several basic structural forms that serve as the foundation for Chinese character shapes. Broadly speaking, these can be categorized into three primary patterns:
・ The square (e.g., 田, 水, 区)
・ The vertically elongated rectangle (e.g., 月, 日, 目, 了, 曽, 員)
・The horizontally elongated rectangle (e.g., 四, 之, 皿, 謝, 縦, 心)
In practice, however, Chinese character shapes can be further classified into more specific geometric forms, such as:
・ Triangles (e.g., 上)
・ Inverted triangles (e.g., 下)
・ Rhombuses (e.g., 寺)
・ Trapezoids (e.g., 尺)
This diversity in structure contributes to the expressive beauty and visual richness of Chinese characters.
That said, all kanji practice books and handwriting guides used in schools rely on square grid lines. As a result, learners must develop the skill to fit each character harmoniously within a square frame, adjusting the character’s proportions and internal balance accordingly.
For example, the character 「日」 (meaning “sun” or “day”) is typically written with the proportions of a vertically elongated rectangle. In contrast, the 「日」 component in the character 「旧」(“old”) must fit within the limited space of the right half of a square, so it is written as large as possible horizontally within that area, resulting in a slightly wider, more square-like shape. Meanwhile, the vertical stroke 「丨」 on the left side is placed slightly closer to the vertical center line of the overall square. By positioning the 「丨」 and 「日」 in this way, the entire character 「旧」 appears visually balanced and takes on the shape of a well-proportioned square.
Because of this structural constraint, the standalone character 「日」 and the 「日」 component within 「旧」 often appear nearly identical in size and width—whether in handwriting or digital typefaces. This kind of visual adjustment is a subtle yet essential technique for maintaining aesthetic balance. Being able to skillfully adapt character forms within a fixed square is a foundational aspect of writing Chinese characters well.
In Japan, many children begin attending calligraphy classes as early as their first year of elementary school. These lessons often continue for three to four years, typically once a week. Using brush and ink, students repeatedly practice writing kanji, gradually developing an intuitive sense of proportion and visual harmony. Although they are not explicitly taught which geometric category each character belongs to, this awareness emerges naturally through repetition and observation.
A similar learning process likely takes place in China, where students also internalize the structural and aesthetic principles of Chinese characters through calligraphy and writing practice.