A forgotten link between Chinese Spring Festival and Vasanta Ritu

The Spring Festival marks the beginning of the Chinese New Year. Contrary to what many expect, it is not the first day of the first month of the year, but 23rd day of the 12th lunar month (last month) of the Chinese calendar. It marks the beginning of the spring season, hence the name Spring Festival.

Since ancient times, India too celebrates a festival called Vasanta Panchami which means the fifth day of spring (vasanta ṛtu), dedicated to Goddess Saraswati. Specifically, it is the fifth day of the lunar month Māgha (māgha-ṡukla-pan̄camī).

Now take a look at the following observation.

Do you notice a pattern? Yup! The Chinese New Year mostly begins on the first day of Māgha-māsa, the fifth day of which is also Spring festival (Vasanta Panchami) in India! Is that a mere coincidence or is there some history to it? Sometimes, the Indian calendar is ahead of the Chinese one by exactly one month (Phālguṇa instead of Māgha) because of the former’s need to keep up with sidereal system.

In the Vedic days, Māgha was also the first month of the Indian year and the first month of Vasanta ṛtu. Sometime after the later Vedic period (~500 BCE), Indians switched to Caitra-māsa as the first month of the New Year, which as chosen as the first month of Vasanta ṛtu (spring season). Māgha is also the first month as per many Puranas (Brahmāṇḍa-purāṇa 2.24.141 etc.). The Vedāṅga jyōtiṣa calendar was a tropical lunisolar calendar, just like the current Chinese calendar (and Hebrew calendar), which is designed to keep in sync with the seasons. Unfortunately nowadays, Hindus and Buddhists use the sidereal lunisolar calendar which has drifted away with the seasons. Any sidereal calendar, by definition, cannot be in sync with seasons because it tracks the position of moon w.r.t a distant fixed star (e.g Citra at 0°, Revati at 29°50’ etc.) – that is, the sidereal year – instead of the tropical year.

Digression into seasons

Following is a mapping between various month names. The mapping among columns 2, 3 and 4 is well-known and fixed because these are all lunar. The last three columns are approximations because seasons (ṛtus) and solar months do not map 1-to–1 to lunar months.

Concerning the Ṛtus, there are four options in two variables (tropical/sidereal, Māgha/Caitra):

1. Use sidereal lunar months (usual drik panchanga with Lahiri ayanamsa), assign Caitra (Madhu) as first month of the year, corresponding to Vasanta Ṛtu. This is the current practice in much of modern India. Example dates are 13-Apr–2021, 02-Apr–2022, 22-Mar–2023, 09-Apr–2024, 30-Mar–2025, 19-Mar–2026, etc. These Mar-Apr are a bit late to be called spring and more properly called summer.
2. Use sidereal lunar months (usual drik panchanga with Lahiri ayanamsa), assign Māgha (Tapas) as the first month of the year, corresponding to Vasanta Ṛtu (similar, but not exactly Vedic usage). Examples of Māgha (nirayana) Vasanta Pan̄camī are 16-Feb–2021, 05-Feb–2022, 26-Jan–2023, 14-Feb–2024, 02-Feb–2025, 22-Feb–2026, etc. – exactly same list of dates as the next option below! This reckoning also coincides with Chinese Spring Festival (New Year) as we see in the table above. See below for downsides.
3. Use tropical lunar months and begin the year with Māgha māsa as Vasanta ṛtu. A festival like Vasanta pan̄camī coincides in Vasanta ṛtu, and this option is aligned with Vedic usage (see the argument of Dr. Sammod Acharya). Note that in the Vedic times, the new year used to begin in the month of Māgha (Tapas), also corresponding to Vasanta ṛtu – however it was the tropical lunar month. That is, Māgha was assigned to whichever Ṡukla-pratipada closer to winter solstice (Dec 22), just like the Chinese Zhuanxu calendar. This is quite bad choice because December-January is in no way spring season (vasanta) anywhere in India. It is winter season. We can move Vasanta Pan̄camī to Phālguṇa (instead of Māgha) month which is also Vasanta ṛtu anyway. Example dates of Phālguṇa (sāyana) Vasanta Pan̄camī are 16-Feb–2021, 05-Feb–2022, 26-Jan–2023, 14-Feb–2024, 02-Feb–2025, 22-Feb–2026, etc.
4. Use tropical lunar months and begin the year with Caitra māsa as Vasanta ṛtu. This aligns well with actual, observed spring season in India (Feb-Mar). The downside is that a festival like (Māgha/Phālguṇa) Vasanta pan̄camī doesn’t occur in Vasanta ṛtu but few weeks previously (in Ṡiṡira ṛṭu). We can instead choose Caitra Pan̄camī to celebrate. Examples of Caitra (sāyana) Vasanta Pan̄camī are 18-Mar–2021, 07-Mar–2022, 24-Feb–2023, 14-Mar–2024, 04-Mar–2025, 23-Mar–2026, etc. These dates actually make sense in observed reality! They also coincide with mypanchang.com’s recommendation. This is also the order given in table above.

Note that in all of the above, we do not make any reference to the twelve zodiac signs – they are all independent of 12 rāṡis and independent of any sidereal ayanamsha! That is, we’re talking of the lunisolar calendar, not the tropical solar calendar a la Gregorian/Western calendar.

Another problem using sidereal months is the uncertainty about dates if they fall in the cracks of an adhika-māsa (intercalary month), because it is dependent on the chosen ayanamsha. For example, if you choose Citrapakṣa (Lahiri), the year 2023 has adhika-ṡrāvaṇa but not if you choose Rēvatīpakṣa (Usha-Shashi), which instead gives adhika-phālguṇa in 2024. Any date in the middle is hence ambiguous. For example, 21/Aug/2023 is Nija-Ṡrāvaṇa S5 in Citrapakṣa ayan., Adhika-Bhādrapada S5 in Puṣyapakṣa ayan., Bhādrapada S5 (neither “nija” nor “adhika”) in Rēvatīpakṣa ayan.

Using a tropical lunisolar calendar, the question of ayanamsha doesn’t arise at all and hence unambiguous.

My Proposal

Let’s review a few requirements, say:

1. Vasanta Pan̄camī should occur in one of the two months of Vasanta ṛtu.
2. The New Year should start in Vasanta ṛtu.
3. Cāturmāsya starts in Varṣā ṛtu.

We can satisfy all these if we assume that Vasanta ṛtu starts in tropical Phālguṇa aka sidereal Māgha (last column “My ṛtu” in above table). Thus:

1. Vasanta Pan̄camī being fixed on their respective ṡukla-pan̄camī.
2. The New Year begins on the ṡukla-pratipadā of next month, namely tropical Caitra aka sidereal Phālguṇa.
3. Varṣā ṛtu hence begins in tropical Āṡāḍha or sidereal Ṡrāvaṇa. Traditionally Cāturmāsya vrata happens in the 4 months of (nirayana) Āṡāḍha-ṡukla-ēkādaṡī to Kārtīka-ṡukla-ēkādaṡī.

Drik Panchang, My Panchang and the Rashtriya Panchang (pdf, pg. 115) instead fix the date of Vasanta ṛtu as 19-Feb to 19-Apr (“Drik Ritu”) irrespective of lunar or solar tithi/māsa. Specifically, the Rashtriya Panchang also lists Phālguṇa (fixed as 19-Feb onwards) as the first month of Vasanta Ritu, so we have some precedence.

One may be tempted to choose sidereal Māgha as the beginning of Vasanta ṛtu. In recent years, this occurs in Jan-Feb, so somewhat fits observed seasons (“Drik Ritu” above). However, due to precession of equinoxes, when we interpolate backwards, sidereal Māgha occurs in December or ever earlier! For example, in the year –3000 (proleptic Greogiran), tropical Phālguṇa starts Feb 16 whereas sidereal Māgha starts Nov 20, –3000 which is really pre-winter season.

Seasons are always tied to the Sun, so a tropical calendar gives correct results. You can generate such an almanac using the “Jagannath Hora” software. Click Preferences -> Related to Calculations -> Drik Siddhanta. Then select “Tropical (sāyana)” under Ayanamsa. Optionally, you can tick the check box which says “Use sidereal zodiac for nakshatras” (default to True Citra/Lahiri, you can further customize by adding or subtracting an offset of your chosen Ayanamsha from Lahiri, e.g. subtract 3°47’ to enforce Usha-Shashi) – doing so, the lunar māsā (incl. adhika-māsa) and tithi tied to tropical but the position of the Sun, Moon, etc. is given in terms of sidereal nakṣatra-pāda, which is where you can find them in the night sky.

If you don’t click that checkbox (default), you end up using tropical lunar mansions:

1. Citrā nakṣatra (tropical) occurs on the next day after Pūrṇimā (amānta caitra-kṛṣṇa-pratipadā) instead of occuring on Pūrṇimā day as in sidereal lunar month of Caitrā.
2. Viṡākhā nakṣatra (tropical) occurs on the next day after Pūrṇimā (amānta vaiṡākha-kṛṣṇa-pratipadā) instead of occuring on Pūrṇimā day as in sidereal lunar month Vaiṡākhā.

and so on. In some years, in the months Jyēṣṭha-Āṡāḍha, their namesake nakṣatra is on Pūrṇimā day.

In general, the nakṣatra of that tropical lunar month occurs within ±1 day of Pūrṇimā, which is an ok compromise w.r.t sidereal calendar. The exact sync on Pūrṇimā is noted especially on or after an adhika-māsa.

N.B: If you choose Pūrṇimānta tropical, the nija-adhika-māsa is sandwiched between adhika-māsa! First fifteen days of adhika-masa occur before the nija-masa and the remaining 15 days occur after the nija-masa. This is quite a mess.

Vasanta ṛtu is in Jan-Feb and not Mar-Apr

Traditionally the spring season is determined as that time during which the mango tree blooms out its flowers. This normally happens in Jan-Feb in various parts of the country. Even today Vasantotsav is celebrated in Jan in Maharashtra, Feb in Gujarat, Phalguna (Holi) in Bengal. The traditional Vasanta Panchami aka Saraswati Puja occurs in Jan or Feb only. Even the Chinese celebrate their New Year (Spring Festival) in Jan or Feb only. In short, “spring” season means the months of Jan-Feb throught history and geography.

However, a later trend started that the months of Caitra and Vaiṡākha (Mar-Apr) are “Vasanta ṛtu”. Caitra may be sometimes pass for “spring” season but there is no one who celebrates Vaiṡākha month as spring season. It (Apr-May) is proper summer, not spring. There is no historical celebration.

Exploring the Tropical Lunisolar Calendar

Summarising the above:

1. Use Tropical (sāyana) amānta lunisolar calendar for month names.
2. New Year starts on Caitra-ṡukla-pratipada.
3. Seasons are mapped in pairs starting with Vasanta Ṛtu as Phālguṇa-Caitra.
4. Adhika-māsa occurs cyclically during any of the twelve possible months.

Let us compare popular Hindu festivals.

As you can see, the Sāyana festivals occur 1 month ± 1 day earlier than Nirayana dates, except in the case of an adhika-māsa, in which case they overlap (e.g. Narasiṃha jayantī).

Conversely, consider a fixed date, say Ṡrī Rāma navamī across 7000 years:

As you can see, Sāyana dates are consistently occuring in March (as expected), whereas the Nirayana dates span anywhere between January to early May!