fuzzyworld

when-am-i / files / src / data / calendars / vietnam.json

vietnam.json

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f24ee458 2026-06-21 Pavel Safronov1{
2 "region": {
3 "name": "Vietnam",
4 "geo": {
5 "type": "Polygon",
6 "coordinates": [
7 [
8 [108.1, 21.6],
9 [106.7, 20.7],
10 [105.9, 19.8],
11 [105.7, 19.1],
12 [106.4, 18.0],
13 [107.4, 16.7],
14 [108.3, 16.1],
15 [108.9, 15.3],
16 [109.3, 13.4],
17 [109.2, 11.7],
18 [108.4, 11.0],
19 [107.2, 10.4],
20 [106.4, 9.5],
21 [105.2, 8.6],
22 [104.8, 9.2],
23 [105.1, 9.9],
24 [104.3, 10.5],
25 [105.2, 10.9],
26 [106.2, 11.0],
27 [105.8, 11.6],
28 [107.5, 12.3],
29 [107.6, 13.5],
30 [107.4, 14.2],
31 [107.6, 15.2],
32 [107.3, 15.9],
33 [106.6, 16.6],
34 [105.9, 17.5],
35 [105.1, 18.7],
36 [103.9, 19.3],
37 [104.2, 19.6],
38 [104.8, 19.9],
39 [104.4, 20.8],
40 [103.2, 20.8],
41 [102.8, 21.7],
42 [102.2, 22.5],
43 [102.7, 22.7],
44 [103.5, 22.7],
45 [104.5, 22.8],
46 [105.3, 23.4],
47 [105.8, 23.0],
48 [106.7, 22.8],
49 [106.6, 22.2],
50 [107.0, 21.8],
51 [108.1, 21.6]
52 ]
53 ]
54 }
55 },
56 "eras": [
57 {
58 "name": "Traditional lunisolar calendar (pre-1954)",
59 "start": null,
60 "end": "1954-01-01",
61 "calendar": "Vietnamese lunisolar calendar",
62 "usedBy": "the Vietnamese",
63 "description": "For most of recorded history Vietnam used a lunisolar calendar derived from Chinese models, recalculated by court astronomers under successive dynasties (recorded calendar names include Thụ Thời/Hiệp Kỷ from the Trần dynasty in the 1320s, Khâm Thụ under the Lê dynasty from 1413, and a Qing-derived Hiệp Kỷ method under the Nguyễn dynasty from 1813). Years were not numbered continuously; they were cited by the 60-year sexagenary cycle (can chi) or by the reigning emperor's era name and regnal year (e.g. \"Thành Thái canh dần niên\" for 1890), the same conventions used in China and Korea. The Gregorian calendar became Vietnam's official civil calendar in 1954.",
64 "sources": [
65 "https://en.wikipedia.org/wiki/Vietnamese_calendar",
66 "https://en.wikipedia.org/wiki/Tr%E1%BA%A7n_dynasty",
67 "https://en.wikipedia.org/wiki/Nguy%E1%BB%85n_dynasty"
68 ]
69 },
70 {
71 "name": "Gregorian calendar (official)",
72 "start": "1954-01-01",
73 "end": null,
74 "calendar": "Gregorian",
75 "usedBy": "the Vietnamese government",
76 "description": "The Gregorian calendar has been Vietnam's official calendar since 1954. North Vietnam made it the sole official calendar (restricting the lunisolar calendar to holidays and commemorations) by an 8 August 1967 decree that also shifted the country's standard time from UTC+8 to UTC+7; South Vietnam adopted the same restriction at the end of the Vietnam War in 1975.",
77 "sources": [
78 "https://en.wikipedia.org/wiki/Vietnamese_calendar"
79 ]
80 },
81 {
82 "name": "Lunisolar calendar (cultural use, modern)",
83 "start": "1954-01-01",
84 "end": null,
85 "calendar": "Vietnamese lunisolar calendar",
86 "usedBy": "the Vietnamese",
87 "description": "Although no longer the official civil calendar after 1954, the lunisolar calendar remains in everyday cultural use for holidays such as Tết Nguyên Đán (Lunar New Year) and Tết Trung Thu (Mid-Autumn Festival). Since Vietnam's 1967/1975 shift to UTC+7 for its calendar calculations, it can diverge by up to a month from the Chinese calendar (which uses UTC+8): in 1985, for example, Vietnamese New Year fell on 21 January while Chinese New Year fell on 20 February, a gap resolved only when Vietnam inserted its own leap month from 21 March to 19 April that year.",
88 "sources": [
89 "https://en.wikipedia.org/wiki/Vietnamese_calendar"
90 ]
91 }
92 ]
93}