Units of time

Unit of time	Its span or duration as in Amarakośa	Kṣīrasvāmin' s remarks	Arthaśāstra (II.20)
Nimeṣa	-	The time taken for winking of the eye– nimeṣo'kṣispandakālaḥ |	2 lavas
1 Kāṣṭhā (I. 4. 11; p. 34)	18 Nimeṣas	-	5 Nimeṣas
Kalā (I. 4. 11; p. 34)	30 Kāṣṭhas	-	30 Kāṣṭhas
Kṣaṇa (I. 4. 11; p. 34) (III. 3. 47;p.281)	30 Kalās	1/60 nāḍikās– kālaviśeṣo nāḍikāṣaṣṭāṃśaḥ |	-
Truṭi (III. 3.37;p.278)	-	2 kṣaṇas– truṭiḥ kāle'lpe kṣaṇadvaye |
Muhūrta	12 Kṣaṇas	2 ghaṭikas— te kṣaṇā dvādaśa muhuriyarti muhūrto dvighaṭikam |	2 Nāḍikās
Ahorātra	30 muhūrtas	te muhūrtāstriṃśadahnāsahitā rātrirahorātraḥ	30 muhūrtas
Pakṣa	15 Ahorātra	te'horātrāḥ pañcadaśa pacati bhūtāni pakṣaḥ	-

(a) Pakṣa (I. 3. 12; p. 34)–

[Fortnight:]

Amarakośa defines that the month is comprised of two fortnights the bright and dark.

Kṣīrasvāmin explains that in reckoning the calender with respect to the moon, a month has the bright fortnight as former (where the moon waxes) and dark fortnight as latter (where the moon wanes)–

śuklo māsasya pūrvapakṣaḥ kṛṣṇastvaparaḥ yataścaitrasitādyā māsāḥ ||

(b) Māsa (I. 3. 13; p. 34)–

[Month:]

Kṣīrasvāmin derives the word in two ways to suit the various calender reckonings.

To suit the cāndramāna reckoning, Kṣīrasvāmin derives the word māsa to mean ‘that which belongs to the moon’. To suit any other calender reckoning namely the Saura, Sāvana or Nākṣatra the word māsa is derived as:

‘That which measures or by which it is measured’–

māścandrastasyāyaṃ māsa iti nirvacanena cāndreṇa mānenāyam |
saurasāvana—nākṣatramānaistvanyathā masyati mimīte vā |

Thus, it could be percieved that by the time of Kṣīrasvāmin four^[1] kinds of calender reckonings were well established, namely Cāndramāna, Sauramāna, Sāvana and Nākṣatra.

The Siddhāntaśiromaṇi (I. 19-20) explains these reckonings as follows–

‘The time taken by the sun to complete one revolution with respect to the stars is the Sauramāna which is one day for the gods and the demons; the time that elapses between two consecutive new moons or conjunctions of the moon with the sun is called a cāndramāna or a lunar month or simply lunation. This is a day for the manes; The time that elapses between two consecutive sunrises at a place is termed the Sāvana day or civil day. This is called the saurasāvana day and it is also the day of the earth; the nākṣatra day is the time taken by the stars to go round the earth once:

raveścakrabhogorkavarṣaṃ pradiṣṭaṃ dyurātraṃ ca devāsurāṇāṃ tadeva ||
ravīndoryuteḥ saṃyutiryāvadanyā vidhormāsa etacca paitraṃ dyurātram |
inodayadvayāntaraṃ tadarkasāvanaṃ dinam ||
tadeva medinīdinaṃ bhavāsurastu bhabhramaḥ |

The Brāhmasphuṭasiddhānta quoted by Utpala on Bṛhatsaṃhitā (II. p. 40) says that from the saura reckoning one derives the extent of yuga, the year, viṣuvat, ayana, seasons, the increase and decrease in the length of the day and night; from the cāndra the details about tithis, karaṇa, intercalary month or kṣaya month, all acts to be performed at night; from sāvana reckoning sacrifices, the savanas (the three soma libations) the motions of planets, fast, impurities on birth and death, medical treatment, expiations and other religious rites.

The synonyms of 12 months and six seasons are named by Amarakośa (I. 3. 15-20; pp. 34-5).

The names of 12 months are–

1. mārgaśīrṣa,
2. pauṣa,
3. māgha,
4. phālguna,
5. caitra,
6. vaiśākha,
7. jyeṣṭha,
8. āṣāḍha,
9. śrāvaṇa,
10. bhādrapada,
11. āśvina and
12. kārtika.

The names of six seasons are–

1. hemanta,
2. śiśira,
3. vasanta,
4. grīṣma,
5. varṣā and
6. śarad.

(c) Vatsara, Saṃvatsara (I. 3. 13, 20; p. 34-5)–

[Year:]

Amarakośa defines a year^[2] of comprising two ayanas, each ayana consisting six seasons or ṛtus and each ṛtu comprising of 2 months. Amarakośa mentions that the year begins with the month mārgā.

But Kṣīrasvāmin observes that the year begins with the month māgha–

māghādyupakramastato'yanārambhāt |

Kṣīrasvāmin quotes Kātya who also opines that the year begins with mārgā month or the Hemantaṛtu–

yatkātyaḥ ādāya mārgaśīrṣācca dvau dvau māsāvṛtuḥ smṛtaḥ | hemantāddhi vatsarasyārambhaḥ |

Thus Amarakośa suggests the year begins with the month mārga (mārgaśīrṣa) while Kṣīrasvāmin opines that the year begins with māgha month.

In ancient times the year began in different months in different parts of India and for different purposes. At present the year begins either in caitra or kārttika in different parts of India.

Many Vedic passages show that the reckoning was pūrṇimānta and that the year began after the full moon of phālguna and that vasanta was the first season of the year. It is due to this that Mādhava says in his Kālanirṇaya (p. 63) that the Śruti insists on the pūrṇimānta month (paurṇamāsyantatve śruteḥ kaṭākṣo bhūyān). The Smṛticandrikā (p. 377) notes that the amānta reckoning is followed in Deccan and pūrṇimānta in northern India.

The Vedāṅgajyotiṣa says that the first year of the cycle of five years began in māgha śukla i.e., at the winter solstice. Alberuni mentions that the year began in caitra, bhādrapada, kārttika, mārgaśīrṣa in different parts of India.

The etymology rendered by Kṣīrasvāmin for saṃvatsara is noteworthy that,

‘It is in which all seasons exist together or in which the seasons change’.

He justifies his view by quoting the text of Bhāguri and thus opines that the word parivatsara can also be used to denote a year–

saṃvasanti ṛtavo'smin saṃvatsaraḥ, ṛtuparivartātmā hyasau yadbhāguriḥ—sarvartuparivartastu smṛtaḥ saṃvatsaro budhaiḥ | parivatsaropi |

Footnotes and references:

[1]:

The Nārada saṃhitā (III. 1-2) mentions nine kinds of reckonings of time viz.,

1. brāhma (of Brahma),
2. daiva (of the gods),
3. mānuṣa (human),
4. paitrya (of the manes),
5. saura,
6. sāvana,
7. cāndra,
8. nākṣatra and
9. bārhaspatya;

But in ordinary worldly matters only five of these are employed:

brāhmaṃ daivaṃ mānuṣaṃ ca paitryaṃ sauraṃ ca sāvanaṃ ||
cāndramārkṣaṃ gurormānamiti mānāni vai nava |
eṣā tu nava mānāṃ vyavahāro'tra pañcabhiḥ |
teṣāṃ pṛthak pṛthak kāryaṃ vakṣyate vyavahārataḥ ||

[2]:

dvau dvau mārgādi māsau syādṛtustairayanam tribhiḥ | āyane dve gatirudag dakṣiṇārkasya vatsaraḥ |