The modern form of す comes from the cursive form of the kanji 寸 (す(ん), su(n), i.e. “approximately 3.03cm”). Follow the progression of the different scripts shown in Figures 1 to 3 to understand its origin.

figure_1_2_hiragana_su-horz

Figure 1. Standard script (楷書, かいしょ, kaisho) of the kanji 寸.

Figure 2. Semi-cursive script (行書, ぎょうしょ, gyōsho) of the kanji 寸.

figure_3_4_hiragana_su-horz

Figure 3. Cursive script (草書, そうしょ, sōsho) of the kanji 寸.

figure_5_hiragana_su

Figure 4. Calligraphy of the hiragana character す. Note the corresponding shape with the cursive form of the character 寸.

Figure 5. The word すき (suki, i.e. “liking”, “love”) written in Japanese kana (かな) script. The hiragana character き is based on the cursive form of the kanji 幾 (き, ki, i.e.: “how many”, “some”, etc.), which is explained in this article.