A chandramana masa in which no sankramana occurs is known as Adhika Masa. The instant at which Sun transits from one Rashi to the next is called a Sankramana.
Mathematically, a Chandramana Varsha has 354 days, while a Soura Varsha has 365 days, the difference being 11 days per year. In the course of 2 years and 8 months of Chandramana the difference works out to 29.5 days equal to another Chandramana masa. The 33rd masa is considered as an Adhika masa which brings the two systems (Chandramana and Souramana) to evenness. Thus, theoretically, every 33rd chandramana masa is an Adhika masa. In practice, due to the variations in speed of movement of Sun and Moon, Adhika Masa occurs anywhere between 28th and 36th masas.
Malimlucha: Starting with the masa Magha, twelve Adithyas by name Aruna, Soorya, Bhanu, Thapana, Indra, Ravi, Gabasthi, Aryama, Hiranyarethasa, Diwakara, Mithra and Vishnu rise in each masa (one in each masa). No Adithya rises in an Adhika masa. Such a masa with no Adithya is called Malimlucha meaning a Napumsaka - genderless.
Shriman Narayana in the name Purushotthama with Lakshmidevi in the name Ananda is the Masa Niyamaka of Adhika masa. The masa is also referred as Purushotthama masa. Thithythree devathas consisting of Ekadasha Rudras (Eleven Rudras), Dwadashadithyas (Twelve Adithyas), Ashta Vasus (Eight Vasus), Prajapathi and Vashatkara are the devathas of Adhika masa. Their antharyami Bhagavantha is not different from Purushottama, the masa Niyamaka.
The names of Ekadasha Rudras with their antharyami Bhagavantha’s names are: Bheema [Rama], Raivatha [Achyutha], Oja [Purushotthama], Ajaikapath [Govinda], Mahan [Vamana], Bahuroopa [Shreesha], Bhava [Shreekanta], Vamadeva [Vishwasakshi], Ugra [Narayana], Vrushakapi [Madhuripu] and Ahirbudhni [Aniruddha].
The Dwadashadithyas are: Vivaswan [Thrivikrama], Aryama [Vasudeva], Poosha [Jagadyoni], Thwastru [Anantha], Savithru [Sheshashayee], Bhaga [Sankarshana], Dhathru [Pradyumna], Parjanya [Daithyari], Varuna [Vishwathomukha], Mithra [Janardhana], Shakra [Dharavasa], Urukrama [Damodara], Prajapathi [Agardhana] and Vashatkara [Shreepathi].
The Ashtavasus are: Drona [Vishnu], Dhruva [Jishnu], Dosha [Mahavishnu], Arka [Hari], Agni [Krishna], Dyaou [Adhokshaja], Prana [Keshava] and Vibhavasu [Madhava].
Accumulation of Punya is more in a Purushotthama masa giving the masa the name Adhika masa. Bhagavantha will eliminate the papas during the masa giving the masa the name Mala masa. The list of Shubha karyas to be avoided also justifies the name Mala masa.
Bhagavantha will provide Women who observe the Adhika masa with Soubhagya and be blessed with Sons with immense love to God. Snana in Adhika masa will avoid miscarriages. No other masa is equal to the Purushotthama masa.
Vrathas & Danas in Adhika Masa
Masa Snana: Snana during Arunodaya (One and a half hour period before Sunrise) on all days of the masa in rivers / sarovaras / tanks / wells etc.
Ayachitha Vratha: Being content with what you have and not ask anybody for anything.
Akhanda Deepa: One lamp should glow continuously without a break during the entire masa.
Deepa Seva: Lighting of 33 lamps, 108 lamps, 1008 lamps on all days / special days / one day or any combination.
Dharana Parana Vratha: Fifteen cycles of One complete day fasting (dharana) followed by Parana on the next day.
Vishnu Panchaka Vratha: Five fasts during the masa on - Shravana Nakshatra day, Two Ekadashis, Pournami and Amavasya
Naktha Bhojana / Eka Bhuktha: Complete fasting during the day and just One meal at night time.
Thamboola Dana: On all days of the masa to brahmin couples.
Bagina dana: Women should give away baginas to at least 33 mutthaides (sumangalis).
Apoopa Dana: Apoopas prepared out of Rice, Jaggery and Ghee. At least 33 apoopas in a bronze vessel to be given away. Ghee in another vessel also to be given away. This is said to bestow Vishesha Phala.
Phala Dana: Minimum of 33 plantains or mangoes or Jack fruit lozenges.
Those who cannot give on all days of the masa should try and give on the special days: Shukla Dwadashi, Pournima, Krishna Ashtami, Navami, Dwadashi, Chathurdashi and Amavasya.
Note: All danas should be accompanied by Dakshina (cash).
Dakshina is the name of the Lakshmidevi seated to the south of Sriman Narayana. Danas are considered being given to Sriman Narayana and Dakshina to Lakshmidevi by name Dakshina.
Shastras say Dakshina should be equal to the monetary value of the item being given away. Considering what shastras say, Dakshina should not be just a coin.
Vrathas and Danas are complete only with a Samarpane to Bhagavantha. Traditionally, “Bharathi ramana Mukhya Prananthargatha Shri Krishnarpanamastu” is used.
The number 33 mentioned in all the above cases is the minimum indicated and persons who can afford need not limit to 33.
Adhika Masa Na-Karthavyas
Rakshasas by name Nairuthas dominate in the Adhika masa and destroy the phalas of all Kamya karmas - Functions or Vratas with a specific desire are known as Kamya karmas. List of them to be avoided in an Adhika masa are Agnyadheya, Devatha Prathishte, Yajna, Vratas, Upakarma, Vrushothsava, Choodakarma (First haircut), Upanayana, Vivaha, Vasthu devatha pooja, Gruha pravesha, Yathrothsava, Wearing of new ornaments and Mahadanas. Thulapurushadana, Hiranyagarbhadana, Brahmandadana, Kalpapadapada, Gosahasradana are some of the sixteen mahadanas.
Yathrothsava: The ban on yathra is only for those who are going for the first time. Here yathra means those who visit pilgrim centres for darshana and Shraddha.
Karthavyas in Adhika masa
Nithya Sandhyavandana, Devatha Pooja, Vaishwadeva, Pumsavana, Seemantha, Jathakarma, Shanthis associated with it, Masika Shraddha, Sapindeekarana, Varshika Shraddha (for those who have passed away during an Adhika masa), Dana & Japa on Grahana day, Chathurmasya vratha (if the Adhika masa happens to be one of the Chathurmasas), Japas / Archanas etc as Pariharas for illnesses, Japas / Parayanas etc for getting rain, and other routine activities.
A chandramana masa in which TWO sankramanas occur is known as Kshaya Masa. Normally only one Sankramana occurs in each Chandramana masa with the exception of an Adhika Masa.
A Kshaya Masa is also called Shoonya Masa.
TWO Adhika masas: Whenever a Kshaya masa occurs, two Adhika masas occur during the same year. The earlier one is known as Amhaspathi or Prakrutha and the second one as Samsarpa or Malimluncha. Prakrutha Adhika masa is considered normal masa with no stigma of Na-karthavyas.
Activities of a Kshaya masa
During a Kshaya masa, theoretically a masa is lost and all activities during the masa will have to be lost.
In practice, the Kshaya masa gets sort of merged with the next masa. During such a masa, the first half of each thithi is considered to represent the Kshaya masa and the later half the next masa.
Luckily each thithi is divided into two equal halves and are known as Karanas. Therefore the first karana of a thithi refers to the kshaya masa and the later karana to the next masa. Activities of the masas are to be carried out in the respective karanas.
Occurance: Kshaya masa can occur only during Kartheeka, Margashira or Pushya masas.
Next Kshaya masa: Kshaya masas occur alternately once in 141 years and 19 years. Kshaya masa occured in the past during 1983 after a gap of 19 years i.e year 1964. Therefore the next Kshaya masa is expected during 2124.
Details of Shraddha during Adhika Vaishakha Masa
1. Annual shraddhas due in Vaishakha masa are to be performed in Nija Vaishakha masa.
2. First Abdika of persons who passed away during last year’s Vaishakha masa is to be performed during Adhika Vaishakha masa itself.
3. Masika (shraddha) for persons who passed away during last year after Vaishakha masa has to be performed in both Adhika and Nija Vaishakha masas.
4. Darsha shraddha has to be performed during both Adhika and Nija masas.
5. Annual shraddha for those who have passed away during Adhika Vaishalka masa has to be peformed in Adhika Vaishakha masa only. [During years without a Adhika Vaishakha masa, it has to be performed in Vaishakha masa.]