Pitungan is a local term constructed from the word itung meaning to count. The prefix pe- and suffix -an are added to mean the way of calculating, or, simply the numerological system. Associated with the term pitungan is pena'asan, derived from the word na'as meaning bad luck; thus, pitungan and pena'asan mean calculating the value of the number in a numerological system to avoid bad luck. In practice the Cirebonese numerological system has two main objectives. The first is to determine the beginning of the new Javanese calendar year, and the second is to determine preferred dates and times to do important jobs. Both are done mainly by manipulating certain values attached to each calendar unit, for example: day, month, year.

The Cirebonese, as do other Javanese, use a traditional lunar calendar along with the official solar one. Unlike the months and the new years of the solar calendar whose beginning are easily ascertained, determining the new months and, therefore, the new year in the lunar calendar is rather problematic. The moon's orbit (and, therefore, the interval between new moons) is about 29.5 days. Hence, a month is calculated as either 29 or 30 days. Unfortunately, which month should take 29 and which should take 30 cannot be fixed precisely. Each individual month could have either. A certain month may take 29 days one year but the next year it may take 30. This gives rise to difficulty in determining the new months and in turn the new year. To reconcile the differences a certain calculation is employed. This reconciliation is  important as most communal feasts are held on the basis of this calendar, and this calendar is the basis for pena'asan too.

In Cirebon, as well as in most parts of Java, there are two ways of calculating weeks: one is the seven-day week, the other is the five-day pasaran (market-day) week. For each method, each day has its own jejer, or ordinal standing, and naktu (Central Java: neptu). Naktu, a specific value attached to the names of people and calendar units: days of the week, the pasaran, months, years, is a crucial element on which calculations are based. The naktu for the days of the ordinary week and the pasaran week are puit in Table 3.2.

The Cirebonese consider Friday as the most important day of the week and, in relation to pitungan, it is put at the first jejer and, thus, the seven-day week goes from Friday to Thursday. In the pasaran week, on the other hand, Kliwon is considered to be the most important day and is put at the first jejer and, thus, the five-day pasaran week proceeds from Kliwon to Manis, Pahing, Pon and Wage. A most significant moment occurs once every thirty-five days; that is, on Jemuah Kliwon where the first jejer of the seven-day week (Friday) meets the first jejer of  the five-day pasaran week (Kliwon). Friday's significance seems to come from the Islamic tradition that regards Friday as the master of the days (Sayidul Ayyam) for doing religious service. It is unclear, why Kliwon is considered significant although it must be of Javanese tradition. Local literary traditions mention that Friday-Kliwon was traditionally taken by Sunan Gunung Jati as a court assembly day because the day is good for detecting one's intention whether it is good or bad (bisa niteni ala becike niyate wong). It also happens that Sunan Gunung Jati died on “Friday-Kliwon.”

Javanese numerological books (primbon), however, do not place any special importance on Jemuah or Jum'ah Kliwon, nor do they put it on any list of bad days. Friday appears often on lists of good days. It is the day of kemresik (cleansing), an auspicious time for weddings or other feasts during the months of Mulud, Bakdomulud (Cirebon: Sawal Mulud) and Jumadilawal. Friday appears as fair days during Sura and Sapar, whereas in Jumadilakir Friday is inauspicious. A woman born on Jemuah Kliwon is expected to have the characteristics of being ambitious, has the potential for acquiring abundance, and should be careful and frugal, faithful  and considerate to her husband (gedhe butarepane, sinung ing rejeki, setiti lan ngatiati, bekti mring wong lanang, waskita kareping wong lanang).^[48]

Although of less importance, naktu is also calculated for the months of the year and for the years of the windu.^[49] By manipulating these naktu, calculations have been made. In order to establish that the first day of the month Sura of year Alif shall always fall on Rebo (Wednesday) Wage. This is known as the ABOGE system which stands for A-(lif), (Re)-bo, (Wa)-ge. The Aboge is then taken as a fixed point and is used as the basis for subsequent calculations for specific purposes.

Aside from jejer and naktu it is also believed that the position of astronomical objects brings about an ethereal influence on the characteristics of particular times (years, months, days, and even hours). The ethereal condition of certain times will, in turn, affect the result of work done on particular occasions. Certain times which are under the domination of certain astronomical objects will, therefore, be fitting  and beneficial for particular jobs, but not necessarily for others. Finding the best time for doing particular jobs is the second main concern of Cirebonese pitungan and pena'asan.

There are seven astronomical objects that many Cirebonese think have an influence on the work of humans: Syams (Sun), Qamar (Moon), Mirik (Mars), Athorid (Mercury), Musytari (Jupiter), Zuhro (Venus), and Zuhal (Saturn).^[50] The influence of these object are: the Sun, good for almost any work except going to war; Moon, good for any work; Mars, good mainly for making weapons or amulets; Jupiter, not good for any work, although it may be good for going to war; Mercury, like the Sun, good for any work except for going to war, for risky business, or for venturing the chance of large profits; Venus, especially good for religious services  and Saturn, good only for making wells. Everyday of the week from six o'clock in the morning until six o'clock in the afternoon is under their astronomical influence. Each of these ‘planets’ come successively hour after hour to exert temporal dominance. So regularly are their comings that these can be put into an ordered schedule. By merely consulting the schedule one can decide the time at which an important job should be started on a particular day.

For important undertakings, particularly marriages and house building, the month is also of special importance. Of the twelve months, only three are good for marriage, and only four for house building. The months good for marriage are: Raya Agung, Ruwah and Jumadil Akhir. Raya Agung leads the couple to real happiness whereas Ruwah and Jumadil Akhir can bring God's bestowal of abundance. The other months may engender unwanted consequences such as: Sura, a broken marriage; Sapar, overt domination of lust, which may cause betrayal; Mulud, many obstacles; Sawal Mulud, easily being tempted by gossips; Jumadil Awal, frequent loss of belongings; Rejeb, repression; Puasa, betrayal; Syawal, serious debts and Kapit, frequent illness. The months good for building houses and the expected benefit are: Puasa, acquiring precious valuables; Raya Agung, bringing abundance; Kapit, good for farms and raising livestock and Jumadil Awwal, attracting many friends; Jumadil Akhir, facing no serious trouble. Fair months for building a house are: Rejep, which causes a tendency of staying indoors and provokes laziness and a feeling of isolation; Ruwah, makes people hesitant to approach the occupants. Bad months are: Sura, and Sawal Mulud, which will cause the builder to encounter some trouble; Sapar and Mulud are even worse.

In some cases, one cannot wait until a good time comes, but one must avoid the dangerous day called Raspati.^[51] In this case it may be preferable to choose a neutral  time called a dina lowong (literally, meaning vacant day) when neither advantageous nor disadvantageous consequences may result. To this end, a person has to find out either the neutral day on which he could do a job or the Raspati on which he is to avoid doing a job. Dina lowong is basically any day of the month which does not coincide with pasaran Kliwon. Determining this day can be done by calculation, by memory, or by consulting written records of the first pasaran day of the month under consideration, then by counting from this pasaran day to Pahing. An example for the use of this method is: the first day of Sura year Alif must fall on Rebo (Wednesday) Wage; count the pasaran starting from the day after Wage. This makes three days, that is: Wage (uncounted), Kliwon, Manis and Pahing. Three days after Wednesday is Saturday (Pahing). However, if the first day of the month falls on Pahing, the next Pahing (the sixth day of the month) will be a neutral day, a day when one can do a job without a fear of bad consequences or a hope of good ones: paduasal slamet bae (just safe only).

Sometimes a person is very uneasy with Raspati, and he is eager to determine its occurrence in order to avoid it. The formula is simple: Raspati occurs when the value of naktu of the particular month combined with the naktu of the day is either twelve or five. Take twelve, for the first example. Subtract twelve by naktu of the month, the rest is equal to naktu of the day, that is the raspati. Thus, naktu of Syawal is seven. Twelve minus seven makes five; find out a day whose naktu is five (Sunday), which is the raspati for that month. One must therefore, avoid doing important jobs on the Sunday of Syawal. The naktu of Sapar is two; five minus two makes three which is the naktu of Tuesday; one must avoid doing important jobs on Tuesday of Sapar. After doing long and laborious calculations for a few years, Mang Atmo, who is not a dukun, produced a number of comprehensive pena'asan tables applicable  for entire years. As one of the custodians of Kramat Uma Gede (The Great House) at Trusmi, he has many guests, some of whom consult him about pena'asan. Instead of doing laborious calculations he simply consults his ready made hand written tables to serve his clients. For the year Alif, for example, the expected first day of the months, the lowong (neutral) and the raspati (dangerous) days is put in following table.

In addition, by taking the influence of the astronomical objects into account (the items appear in table 3.5), Mang Atmo has also a long list which says about the recommended (good) days, the forbidden (bad) days, dates and pasaran, even hours, for doing important work throughout the entire windu. An example of this list appears in table 3.6.^[52]

In relation to the current use of pitungan, Mang Atmo however claimed that the pitungan system is nothing more than man's ikhtiar, or efforts to follow where  nature seems to go, and that we should therefore not try to go against it. It was invented by our ancestors when our life was so much more dependent on nature. Now our lives are different; people are knowledgeable and do not seem so dependent on nature. He says that when he was a child the harvest occurred only once a year because most sawah relied totally on rain. One had to be careful to catch the best time to start working a sawah, otherwise the work would be ruined; that is why the pitungan system was needed. Now, by virtue of irrigation, harvests occur twice a year and the starting times are far more flexible. In working sawah people no longer care about mangsa (seasons) for agricultural pitungan. However, there are still many aspects of our lives where people think that pitungan is still needed. He then warned that those who believe in pitungan should keep it in proper perspective because it is not the only factor determining good results. Along with individual characteristics including ability, resources and other influencing factors, there is still the final and unavoidable factor, that is, kresane Gusti Allah (God's will). Nevertheless, “bli arep ndingini kresane pengeran” (“without intending to preempt God's will”), he said that he himself still adheres to the pitungan system because sometimes it shows its worth.

To illustrate the worth of pitungan and pena'asan Mang Atmo told about his own son, Harlan, who got into trouble.^[53] In this example Mang Atmo probably wished to imply that if his son had followed his advice based on the pitungan system his son probably would not have fallen into trouble. In other words he wanted to illustrate how pitungan could be a useful means of avoiding unexpected results. This, of course, does not necessarily imply that the pitungan is the only prerequisite for doing something safely. There are many other factors that contribute to failure or success, such as ability, tools, conditions and the atmosphere by which and in which the work is carried out. But if other variables are held constant, the pitungan system  is an additional help. In other words, if two persons have to do something, each having about equal ability, using similar tools, working in the same conditions, facing similar difficulties, the one who takes account of the pitungan system is thought of as having a better chance of coming to a better end.