each fēn subdivided into 100 miǎo (). Using the definition of fēn as 14.4 seconds, each miǎo was 144 milliseconds long. Shùn and niàn Each fen was subdivided into shùn (), and shùn were subdivided into niàn (). The Mahāsāṃghika, translated into Chinese as the Móhēsēngzhī Lǜ (Taishō Tripiṭaka 1425) describes several units of time, including shùn or shùnqǐng () and niàn. According to this text, niàn is the smallest unit of time at 18 milliseconds and a shùn is 360 milliseconds. It also describes larger units of time, including a tánzhǐ () which is 7.2 seconds long, a luóyù () which is 2 minutes 24 seconds long, and a xūyú (), which is of a day at 48 minutes long. During night: Gēng-diǎn system The Gēng-diǎn ( - ) system uses predetermined signals to define the time during the night. One-tenth of a day: Gēng Gēng () is a time signal given by drum or gong. The drum was sounded by the drum tower in city centers, and by night watchman hitting a gong in other areas. The character for gēng , literally meaning "rotation" or "watch", comes from the rotation of watchmen sounding these signals. The first gēng theoretically comes at sundown, but was standardized to fall at yǒu shí central 1 kè, or 19:12. The time between each gēng is of a day, making a gēng 2.4 hours—or 2 hours 24 minutes—long. The 5 gēngs in the night are numbered from one to five: yì gēng () (alternately chū gēng () for "initial watch"); èr gēng (); sān gēng (); sì gēng (); and wǔ gēng (). The 5 gēngs in daytime are named after times of day listed in the Book of Sui, which describes the legendary Yellow Emperor dividing the day and night into ten equal parts. They are morning (); midmorning, (); noon, (); afternoon (); and evening (). As a 10-part system, the gēng are strongly associated with the 10 celestial stems, especially since the stems are used to count off the gēng during the night in Chinese literature. One-sixtieth of a day: Diǎn Diǎn (), or point, marked when the bell time signal was rung. The time signal was released by the drum tower or local temples. Each diǎn or point is of a day, making them 0.4 hours, or 24 minutes, long. Every sixth diǎn falls on the gēng, with the