Mao Collection, Upper Volume Radical: Heart (xīn) Sì Kangxi strokes: 10 Page 384, Entry 20 According to the Collection of Rhymes (Jiyun), this is the ancient form of the character for thought (sī). For a detailed annotation, see the five-stroke entry. The character shape is composed of the components for cranial fontanelle (xìn) and heart (xīn). According to the Refined Essence of the Six Writings (Liushu jingyun), where does the original spirit reside? It resides in the heart. Through what path does the original spirit enter and exit? The cranial fontanelle serves as its gateway.