Six-hour clock

The six-hour clock is a traditional timekeeping system used in Thai and formerly Lao language and Khmer language. alongside the official 24-hour clock. Like the other common systems, it counts twenty-four hours in a day, but divides the day into four quarters, counting six hours in each. The hours in each quarter (with the exception of the sixth) are told with period-designating words or phrases, which are:

• ... mong chao (Thai: ...โมงเช้า, [mōːŋ tɕʰáːw]) for the first half of daytime (07:00 to 12:59)
• Bai ... mong (บ่าย...โมง, [bàːj mōːŋ]) for the latter half of daytime (13:00 to 18:59)
• ... thum (...ทุ่ม, [tʰûm]) for the first half of nighttime (19:00 to 00:59)
• Ti ... (ตี..., [tīː]) for the latter half of nighttime (01:00 to 06:59)

These terms are believed to have originated from the sounds of traditional timekeeping devices. The gong was used to announce the hours in daytime, and the drum at night. Hence the terms mong, an onomatopoeia of the sound of the gong, and thum, that of the sound of the drum. Ti is a verb meaning to hit or strike, and is presumed to have originated from the act of striking the timekeeping device itself.^[1] Chao and bai translate as morning and afternoon respectively, and help to differentiate the two daytime quarters.

The sixth hours of each quarter are told by a different set of terms. The sixth hour at dawn is called yam rung (ย่ำรุ่ง, [jâm rûŋ]), and the sixth hour at dusk is called yam kham (ย่ำค่ำ, [jâm kʰâm]), both references to the act of striking the gong or drum in succession to announce the turning of day (yam), where rung and kham, meaning dawn and dusk, denote the time of these occurrences. The midday and midnight hours are respectively known as thiang (เที่ยง, [tʰîaːŋ], or thiang wan, เที่ยงวัน, [tʰîaːŋ wān]) and thiang khuen (เที่ยงคืน, [tʰîaːŋ kʰɯ̄ːn]), both of which literally translate as midday and midnight.

Midnight is also called song yam (สองยาม, [sɔ̌ːŋ jāːm], note that yam is a different word), a reference to the end of the second three-hour period of the night watch (song translates as the number two). In addition, hok (6) thum and ti hok may also be used to refer to the hours of midnight and dawn, following general usage for the other hours, although more rarely, and the fourth to sixth hours of the second daytime half may also be told as ... mong yen (...โมงเย็น, [mōːŋ jēn]), yen meaning evening.

The system has been used in some form since the days of the Ayutthaya Kingdom, but was only codified similarly to its present form in 1901 by King Chulalongkorn in Royal Gazette 17:206.^[2] Nowadays, it is used only in colloquial speech. However, a corrupted form of the six-hour clock is more frequently encountered,^[1] where usually the first half of daytime (including the sixth hour of the preceding quarter) is counted as in the twelve-hour clock, i.e. hok (6) mong chao, chet (7) mong, etc. up to sip et (11) mong.

Six-hour clock system has been abolished in Laos and Cambodia during the French protectorate, and the French 24-hour clock system (for example 3h00) has been used.

A comparison of the systems is as follows:

^* The word chao (เช้า) is optional here since the numbers 7 to 11 are not used elsewhere

^** Conversationally, si mong yen (สี่โมงเย็น) and ha mong yen (ห้าโมงเย็น) are also spoken if considered as evening

References

1. ^ ^{a b} Thongprasert, Chamnong (1985), "ทุ่ม-โมง-นาฬิกา (Thum-Mong-Nalika)", ภาษาไทยไขขาน (Thai Unlocked), Bangkok: Prae Pitaya Press, pp. 229–237, http://www.royin.go.th/th/knowledge/detail.php?ID=1273 . (Thai)
2. ^ "ประกาศใช้ทุ่มโมงยาม", Royal Gazette (17): 206, 29 July 1901, http://www.ratchakitcha.soc.go.th/DATA/PDF/2443/018/206.PDF, retrieved 2008-10-18 . (Thai)

• Royal Institute (2003), พจนานุกรม ฉบับราชบัณฑิตยสถาน พ.ศ. ๒๕๔๒ (Royal Institute Dictionary, BE 2542), Bangkok: Nanmee Books Publications, ISBN 974-9588-04-5 . (Thai)

See also

• Time in Thailand
• Thai numerals