B - Marian Calendar Tables
Common and Leap Year Structures
B.1 Purpose
This appendix provides the principal structural tables for the Marian Calendar.
It shows the two regular annual templates, the twelve months, twenty-four minths, four quarters, six Sixths and the valid weekday positions at shortened terminal weeks. The tables are derived from the normative rules in Appendix A and are intended as a practical reference for readers, software implementers and future standards work.
Unless otherwise stated, ordinal sol numbers begin with Sol 1 on the first sol of the Marian year.
MY0 is excluded because it is a transitional epoch interval rather than a regular Marian year.
B.2 The two annual templates
Marian has only two regular year forms.
| Property | Common year | Leap year |
|---|---|---|
| Total sols | 668 | 669 |
| Months | 12 | 12 |
| Minths | 24 | 24 |
| Sixths | 6 | 6 |
| Quarters | 4 | 4 |
| Nominal week positions | 96 | 96 |
| 56-sol months | 8 | 9 |
| 55-sol months | 4 | 3 |
| 28-sol minths | 20 | 21 |
| 27-sol minths | 4 | 3 |
| Six-position terminal civil weeks | 4 | 3 |
The common-year month pattern is:
56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55
The leap-year pattern differs only at the final position:
56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 56
The additional leap sol is therefore the final sol of Month 12. Nothing earlier in the annual template changes.
B.3 The twelve months
The following table gives the complete month structure. Because Months 1 through 11 are identical in common and leap years, separate ordinal ranges are required only for the final endpoint of Month 12.
| Month | Quarter | Sixth | Minths | Common length | Leap length | Ordinal sols |
|---|---|---|---|---|---|---|
| 1 | Q1 | S1 | 01–02 | 56 | 56 | 1–56 |
| 2 | Q1 | S1 | 03–04 | 56 | 56 | 57–112 |
| 3 | Q1 | S2 | 05–06 | 55 | 55 | 113–167 |
| 4 | Q2 | S2 | 07–08 | 56 | 56 | 168–223 |
| 5 | Q2 | S3 | 09–10 | 56 | 56 | 224–279 |
| 6 | Q2 | S3 | 11–12 | 55 | 55 | 280–334 |
| 7 | Q3 | S4 | 13–14 | 56 | 56 | 335–390 |
| 8 | Q3 | S4 | 15–16 | 56 | 56 | 391–446 |
| 9 | Q3 | S5 | 17–18 | 55 | 55 | 447–501 |
| 10 | Q4 | S5 | 19–20 | 56 | 56 | 502–557 |
| 11 | Q4 | S6 | 21–22 | 56 | 56 | 558–613 |
| 12 | Q4 | S6 | 23–24 | 55 | 56 | 614–668 / 614–669 |
The recurring common-year pattern can also be read quarter by quarter:
| Quarter | Month pattern | Length |
|---|---|---|
| Q1 | 56 – 56 – 55 | 167 |
| Q2 | 56 – 56 – 55 | 167 |
| Q3 | 56 – 56 – 55 | 167 |
| Q4 | 56 – 56 – 55 | 167 |
In a leap year, Q4 becomes:
56 – 56 – 56 = 168 sols
B.4 The twenty-four minths
Each Marian month contains two minths. The first minth always contains 28 sols. The second contains 28 sols in a 56-sol month and 27 sols in a 55-sol month.
| Minth | Shorthand | Month | Length: common | Length: leap | Ordinal sols |
|---|---|---|---|---|---|
| 01 | A | 1 | 28 | 28 | 1–28 |
| 02 | B | 1 | 28 | 28 | 29–56 |
| 03 | C | 2 | 28 | 28 | 57–84 |
| 04 | D | 2 | 28 | 28 | 85–112 |
| 05 | E | 3 | 28 | 28 | 113–140 |
| 06 | F | 3 | 27 | 27 | 141–167 |
| 07 | G | 4 | 28 | 28 | 168–195 |
| 08 | H | 4 | 28 | 28 | 196–223 |
| 09 | I | 5 | 28 | 28 | 224–251 |
| 10 | J | 5 | 28 | 28 | 252–279 |
| 11 | K | 6 | 28 | 28 | 280–307 |
| 12 | L | 6 | 27 | 27 | 308–334 |
| 13 | M | 7 | 28 | 28 | 335–362 |
| 14 | N | 7 | 28 | 28 | 363–390 |
| 15 | O | 8 | 28 | 28 | 391–418 |
| 16 | P | 8 | 28 | 28 | 419–446 |
| 17 | Q | 9 | 28 | 28 | 447–474 |
| 18 | R | 9 | 27 | 27 | 475–501 |
| 19 | S | 10 | 28 | 28 | 502–529 |
| 20 | T | 10 | 28 | 28 | 530–557 |
| 21 | U | 11 | 28 | 28 | 558–585 |
| 22 | V | 11 | 28 | 28 | 586–613 |
| 23 | W | 12 | 28 | 28 | 614–641 |
| 24 | X | 12 | 27 | 28 | 642–668 / 642–669 |
The four shortened common-year minths are therefore:

Detailed figure description
A printed-style annual calendar lays out twelve named Marian months in a multi-panel grid. The recurring seven weekday headings and numeric positions illustrate how months reuse stable weekly layouts. The 55-sol months terminate after the sixth weekday position in the final week, while longer months include the seventh. The exact integer year template is specified in Appendix B; the illustration is a visual reading aid.
Editorial note: this is a descriptive summary, not an independently verified transcription of every diagram label. Refer to the surrounding text and the Marian technical specification for authoritative numeric details where applicable.
06 · 12 · 18 · 24
In a leap year, Minth 24 gains the leap sol and contains 28 sols. The shortened leap-year minths are therefore:
06 · 12 · 18
Every minth begins at weekday position 1.
B.5 Quarters
The four Marian quarters divide the twelve-month annual frame into four groups of three months.
| Quarter | Name | Months | Minths | Common sols | Leap sols | Ordinal range |
|---|---|---|---|---|---|---|
| Q1 | Primiv | 1–3 | 01–06 | 167 | 167 | 1–167 |
| Q2 | Secondiv | 4–6 | 07–12 | 167 | 167 | 168–334 |
| Q3 | Tertiv | 7–9 | 13–18 | 167 | 167 | 335–501 |
| Q4 | Quartiv | 10–12 | 19–24 | 167 | 168 | 502–668 / 502–669 |
Every common-year quarter therefore has the same internal month pattern:
56 + 56 + 55 = 167 sols
The leap sol belongs to Q4 only.
B.6 Sixths
The six Marian Sixths divide the annual frame into six groups of two months.
| Sixth | Name | Months | Minths | Common sols | Leap sols | Ordinal range |
|---|---|---|---|---|---|---|
| S1 | Primus | 1–2 | 01–04 | 112 | 112 | 1–112 |
| S2 | Secundus | 3–4 | 05–08 | 111 | 111 | 113–223 |
| S3 | Tertius | 5–6 | 09–12 | 111 | 111 | 224–334 |
| S4 | Quartus | 7–8 | 13–16 | 112 | 112 | 335–446 |
| S5 | Quintus | 9–10 | 17–20 | 111 | 111 | 447–557 |
| S6 | Sextus | 11–12 | 21–24 | 111 | 112 | 558–668 / 558–669 |
The common-year Sixth pattern is therefore:
112 – 111 – 111 – 112 – 111 – 111
The leap-year pattern is:
112 – 111 – 111 – 112 – 111 – 112
Quarters and Sixths are independent annual grids. Their boundaries coincide only where the month grouping happens to make them coincide.
B.7 Week structure within a month
Every Marian month contains eight nominal civil weeks.
A 56-sol month consists of eight complete seven-position weeks:
| Week | Month sols | Valid weekday positions |
|---|---|---|
| 1 | 1–7 | 1–7 |
| 2 | 8–14 | 1–7 |
| 3 | 15–21 | 1–7 |
| 4 | 22–28 | 1–7 |
| 5 | 29–35 | 1–7 |
| 6 | 36–42 | 1–7 |
| 7 | 43–49 | 1–7 |
| 8 | 50–56 | 1–7 |
A 55-sol month differs only in its final civil week:
| Week | Month sols | Valid weekday positions |
|---|---|---|
| 1 | 1–7 | 1–7 |
| 2 | 8–14 | 1–7 |
| 3 | 15–21 | 1–7 |
| 4 | 22–28 | 1–7 |
| 5 | 29–35 | 1–7 |
| 6 | 36–42 | 1–7 |
| 7 | 43–49 | 1–7 |
| 8 | 50–55 | 1–6 |
The seventh weekday position of Week 8 does not exist in a 55-sol month.
The following month nevertheless begins at:
Week 1 · Day 1
The physical sequence of sols remains continuous. Only the seventh weekday label is absent from the shortened terminal civil week.
B.8 Week structure within a minth
A 28-sol minth consists of four complete seven-position weeks:
7 + 7 + 7 + 7 = 28 sols
A 27-sol minth consists of:
7 + 7 + 7 + 6 = 27 sols
The final week of a 27-sol minth therefore contains weekday positions 1 through 6 only.
| Minth length | Weeks 1–3 | Week 4 |
|---|---|---|
| 28 sols | Positions 1–7 | Positions 1–7 |
| 27 sols | Positions 1–7 | Positions 1–6 |
Because shortened minths occur only as the second minth of a shortened month, the missing seventh position is simultaneously:
Minth Week 4 · Day 7
and:
Month Week 8 · Day 7
It is one absent civil position described at two structural scales.
B.9 Terminal-week validity by month
For most dates, Marian validity is straightforward: Weeks 1 through 7 of every month contain all seven weekday positions. Only Week 8 · Day 7 can vary.
| Month | Common year W8·D7 | Leap year W8·D7 | Result |
|---|---|---|---|
| 1 | Valid | Valid | Month contains 56 sols |
| 2 | Valid | Valid | Month contains 56 sols |
| 3 | Invalid | Invalid | Month ends at W8·D6 |
| 4 | Valid | Valid | Month contains 56 sols |
| 5 | Valid | Valid | Month contains 56 sols |
| 6 | Invalid | Invalid | Month ends at W8·D6 |
| 7 | Valid | Valid | Month contains 56 sols |
| 8 | Valid | Valid | Month contains 56 sols |
| 9 | Invalid | Invalid | Month ends at W8·D6 |
| 10 | Valid | Valid | Month contains 56 sols |
| 11 | Valid | Valid | Month contains 56 sols |
| 12 | Invalid | Valid | Leap-sol position |
The only civil date whose validity depends upon leap status is therefore:
Month 12 · Week 8 · Day 7
That position is the Marian leap sol.
B.10 Terminal transitions
The end of every 56-sol month is:
Month n · Week 8 · Day 7
followed by:
Month n+1 · Week 1 · Day 1
The end of every 55-sol month is:
Month n · Week 8 · Day 6
followed immediately by:
Month n+1 · Week 1 · Day 1
The physical sol following Day 6 therefore receives the first weekday label of the new month rather than the unused seventh label of the old one.
For the four common-year quarter boundaries:
| Boundary | Final date before boundary | Next date |
|---|---|---|
| Q1 → Q2 | M3 · W8 · D6 | M4 · W1 · D1 |
| Q2 → Q3 | M6 · W8 · D6 | M7 · W1 · D1 |
| Q3 → Q4 | M9 · W8 · D6 | M10 · W1 · D1 |
| Q4 → next year | M12 · W8 · D6 | Next MY · M1 · W1 · D1 |
In a leap year, the final transition differs:
M12 · W8 · D7 → next MY · M1 · W1 · D1
This is why every regular Marian year, month and minth begins at weekday position 1 despite the physical year containing 668 or 669 sols rather than an integer number of ordinary seven-sol weeks.
B.11 Common-year terminal positions
The four shortened terminal civil weeks in a common year occur at:
| Location | Ordinal sols in terminal week | Last valid position | Missing position |
|---|---|---|---|
| Month 3, Week 8 | 162–167 | Day 6 = Sol 167 | Day 7 |
| Month 6, Week 8 | 329–334 | Day 6 = Sol 334 | Day 7 |
| Month 9, Week 8 | 496–501 | Day 6 = Sol 501 | Day 7 |
| Month 12, Week 8 | 663–668 | Day 6 = Sol 668 | Day 7 |
The corresponding shortened minths are:
| Minth | Ordinal range | Final valid position |
|---|---|---|
| 06 | 141–167 | Week 4 · Day 6 |
| 12 | 308–334 | Week 4 · Day 6 |
| 18 | 475–501 | Week 4 · Day 6 |
| 24 | 642–668 | Week 4 · Day 6 |
B.12 Leap-year terminal positions
A leap year restores the final weekday position of Month 12 only.
The shortened terminal civil weeks are therefore:
| Location | Ordinal sols in terminal week | Last valid position | Missing position |
|---|---|---|---|
| Month 3, Week 8 | 162–167 | Day 6 = Sol 167 | Day 7 |
| Month 6, Week 8 | 329–334 | Day 6 = Sol 334 | Day 7 |
| Month 9, Week 8 | 496–501 | Day 6 = Sol 501 | Day 7 |
| Month 12, Week 8 | 663–669 | Day 7 = Sol 669 | None |
The final minth changes accordingly:
| Minth | Common year | Leap year |
|---|---|---|
| 24 | 27 sols; ends W4·D6 | 28 sols; ends W4·D7 |
Thus:
MY leap sol = Month 12 · Minth 24 · Month Week 8 · Minth Week 4 · Day 7 · Ordinal Sol 669
These are different coordinate descriptions of the same physical sol.
B.13 Common-year structure at a glance
The complete common-year annual frame is:
| Quarter | Months | Month lengths | Sixths crossing region | Minths | Ordinal sols |
|---|---|---|---|---|---|
| Q1 | 1–3 | 56 · 56 · 55 | S1, part of S2 | 01–06 | 1–167 |
| Q2 | 4–6 | 56 · 56 · 55 | part of S2, S3 | 07–12 | 168–334 |
| Q3 | 7–9 | 56 · 56 · 55 | S4, part of S5 | 13–18 | 335–501 |
| Q4 | 10–12 | 56 · 56 · 55 | part of S5, S6 | 19–24 | 502–668 |
In compact form:
12 months:
56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55
24 minths:
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 27
6 Sixths:
112 – 111 – 111 – 112 – 111 – 111
4 quarters:
167 – 167 – 167 – 167
Total:
668 sols
B.14 Leap-year structure at a glance
The leap-year annual frame is identical until the final civil position:
| Quarter | Months | Month lengths | Minths | Ordinal sols |
|---|---|---|---|---|
| Q1 | 1–3 | 56 · 56 · 55 | 01–06 | 1–167 |
| Q2 | 4–6 | 56 · 56 · 55 | 07–12 | 168–334 |
| Q3 | 7–9 | 56 · 56 · 55 | 13–18 | 335–501 |
| Q4 | 10–12 | 56 · 56 · 56 | 19–24 | 502–669 |
In compact form:
12 months:
56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 55 | 56 – 56 – 56
24 minths:
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 27 |
28 – 28 · 28 – 28 · 28 – 28
6 Sixths:
112 – 111 – 111 – 112 – 111 – 112
4 quarters:
167 – 167 – 167 – 168
Total:
669 sols
B.15 Date-validity quick reference
A regular Marian date is structurally valid if all of the following are true:
| Component | Valid range / rule |
|---|---|
| Month | 1–12 |
| Month week | 1–8 |
| Weekday position | 1–7, subject to terminal-week rule |
| Minth | 01–24 |
| Minth within month | 1 or 2 |
| Minth week | 1–4 |
| Quarter | Q1–Q4 |
| Sixth | S1–S6 |
| Ordinal sol | 1–668 common; 1–669 leap |
For Month Week 8 · Day 7, apply one additional test:
- valid in Months 1, 2, 4, 5, 7, 8, 10 and 11;
- invalid in Months 3, 6 and 9;
- valid in Month 12 only in a leap year.
Equivalently, for a minth date:
- Week 4 · Day 7 is valid in every 28-sol minth;
- invalid in every 27-sol minth.
No other weekday position changes validity between the two regular annual templates.
B.16 The whole architecture in one line
For reference, the common Marian year can be reconstructed from a remarkably small set of relationships:
A common year has 668 sols, arranged as 12 months (56–56–55 ×4), 24 minths, 6 Sixths and 4 quarters.
and the leap year by one additional instruction:
restore the final Day 7 of Month 12 → 669 sols
Everything else in these tables follows from those two statements.