OPEN STUDY / 03

Stems and branches

Explore the sixty-pair cycle with forward and backward steps, wraparound, worked calculations and four self-checks.

About 12 min
Study notes & citation

Stems and branches. Institute of Mantic Arts. https://www.manticarts.com/en/learning/stems-branches

STUDY / OBJECTIVE

Distinguish sequence, counting, parity and the time unit being labeled.

01 / STUDY

A sequence and a date are separate questions

The cycle first provides repeating labels. Knowing a label's position does not identify a calendar date. That requires a reliable reference date, time unit and counting method. The same pair recurs in different rounds, so preserve a larger temporal context.

02 / STUDY

Position numbers and steps moved

A table usually numbers positions one to sixty, while calculations often start at zero. With Jia-Zi at index zero, one step reaches Yi-Chou at index one. Inclusive counting calls these items one and two. Both conventions work, provided the record never switches between them silently.

03 / STUDY

Pairs absent from the cycle

Synchronous movement keeps the stem and branch positions at matching parity. Although arbitrary pairing gives 120 possibilities, this procedure visits only sixty. When a pair is absent, examine transcription, indexing and the material's purpose before silently replacing it with a nearby valid pair.

WORKED EXAMPLE

Check the sequence before attaching a unit

The exercise starts at Jia-Zi and moves twelve steps; no actual date is specified.

  1. Twelve stem steps equal one full round plus two, reaching Bing.

  2. Twelve branch steps complete a round and return to Zi. The resulting pair is Bing-Zi.

  3. This is position thirteen in the table. Record twelve sequence steps, without labeling them years or days.

A step count becomes a time interval only when the input unit is established.

PRACTICE / REFLECTION

Exercises and answers

01Why do neither ten nor twelve steps reset both sequences?

Read the explanation

Ten resets the stems only; twelve resets the branches only. A joint return requires a multiple of both, with sixty the smallest positive value.

02Can “Jia-Zi day” identify a Gregorian date by itself?

Read the explanation

No. The label repeats. Supply a date range and reliable calendar correspondence, retaining alternatives when the evidence is incomplete.

A distinction to retain

Year, month, day and hour labels cannot be converted into one another with this table alone; each application has additional origins and boundaries.

Unit output

Three forward/backward traces, an explanation of an invalid pair and an input card stating its time unit.

REFERENCES

Reading references

References reviewed: 2026-10-24. Examples, record templates and explanations are editorial teaching material. Fictional inputs are not historical events or efficacy evidence. Citations imply no affiliation.

SEQUENCE / PRACTICE

The sixty-pair cycle, step by step

Place the ten stems and twelve branches in their fixed orders. Begin at Jia and Zi, moving both sequences by one place at each step and wrapping each independently. The resulting sixty pairs can be checked against Table 2 in the Hong Kong Observatory reference.

The first joint return takes the least common multiple of 10 and 12: sixty steps. Odd positions pair with odd positions, and even positions pair with even positions. An arbitrary stem and branch therefore need not form a pair in this sequence.

Positive steps move forward; negative steps move backward. Zero keeps the origin. Range: −9999 to 9999. The origin is not counted as a step.

Result 01 / 60甲子Jiǎ–Zǐ

癸亥 + 1 → 甲子

Ten stems

  1. 1甲
  2. 2乙
  3. 3丙
  4. 4丁
  5. 5戊
  6. 6己
  7. 7庚
  8. 8辛
  9. 9壬
  10. 10癸

Twelve branches

  1. 1子
  2. 2丑
  3. 3寅
  4. 4卯
  5. 5辰
  6. 6巳
  7. 7午
  8. 8未
  9. 9申
  10. 10酉
  11. 11戌
  12. 12亥
Calculation trace

Table positions run from 1 to 60; calculation indices run from 0 to 59. Keep the remainder in 0–59, then add 1 to recover the table position.

Starting position
60 − 1 = 59
Steps to move
59 + (1) = 60
mod 60
60 = 60 × (1) + 0
Table position
0 + 1 = 1 · 甲子

The sixty-pair cycle

A gold outline marks the origin; dark green marks the result.

  1. 01甲子Jiǎ–Zǐ
  2. 02乙丑Yǐ–Chǒu
  3. 03丙寅Bǐng–Yín
  4. 04丁卯Dīng–Mǎo
  5. 05戊辰Wù–Chén
  6. 06己巳Jǐ–Sì
  7. 07庚午Gēng–Wǔ
  8. 08辛未Xīn–Wèi
  9. 09壬申Rén–Shēn
  10. 10癸酉Guǐ–Yǒu
  11. 11甲戌Jiǎ–Xū
  12. 12乙亥Yǐ–Hài
  13. 13丙子Bǐng–Zǐ
  14. 14丁丑Dīng–Chǒu
  15. 15戊寅Wù–Yín
  16. 16己卯Jǐ–Mǎo
  17. 17庚辰Gēng–Chén
  18. 18辛巳Xīn–Sì
  19. 19壬午Rén–Wǔ
  20. 20癸未Guǐ–Wèi
  21. 21甲申Jiǎ–Shēn
  22. 22乙酉Yǐ–Yǒu
  23. 23丙戌Bǐng–Xū
  24. 24丁亥Dīng–Hài
  25. 25戊子Wù–Zǐ
  26. 26己丑Jǐ–Chǒu
  27. 27庚寅Gēng–Yín
  28. 28辛卯Xīn–Mǎo
  29. 29壬辰Rén–Chén
  30. 30癸巳Guǐ–Sì
  31. 31甲午Jiǎ–Wǔ
  32. 32乙未Yǐ–Wèi
  33. 33丙申Bǐng–Shēn
  34. 34丁酉Dīng–Yǒu
  35. 35戊戌Wù–Xū
  36. 36己亥Jǐ–Hài
  37. 37庚子Gēng–Zǐ
  38. 38辛丑Xīn–Chǒu
  39. 39壬寅Rén–Yín
  40. 40癸卯Guǐ–Mǎo
  41. 41甲辰Jiǎ–Chén
  42. 42乙巳Yǐ–Sì
  43. 43丙午Bǐng–Wǔ
  44. 44丁未Dīng–Wèi
  45. 45戊申Wù–Shēn
  46. 46己酉Jǐ–Yǒu
  47. 47庚戌Gēng–Xū
  48. 48辛亥Xīn–Hài
  49. 49壬子Rén–Zǐ
  50. 50癸丑Guǐ–Chǒu
  51. 51甲寅Jiǎ–Yín
  52. 52乙卯Yǐ–Mǎo
  53. 53丙辰Bǐng–Chén
  54. 54丁巳Dīng–Sì
  55. 55戊午Wù–Wǔ
  56. 56己未Jǐ–Wèi
  57. 57庚申Gēng–Shēn
  58. 58辛酉Xīn–Yǒu
  59. 59壬戌Rén–Xū
  60. 60癸亥Guǐ–Hài

Four checks of understanding

01 · Move one step forward from position 60, Gui-Hai. Where do you arrive?

Reference explanation

Position 1, Jia-Zi. Gui wraps to Jia and Hai wraps to Zi. This identifies a sequence position; no year, month, day or hour has been assigned.

02 · Do one backward step and 59 forward steps from Jia-Zi reach the same pair?

Reference explanation

Both reach position 60, Gui-Hai. Their paths differ by one full cycle. Equal endpoints do not mean equal distances, so retain the starting point and step count.

03 · Why does Jia-Zi advanced by ten steps keep Jia but lose Zi?

Reference explanation

The ten-stem sequence completes a round, while the twelve-branch sequence reaches Xu. The result is position 11, Jia-Xu. Both sequences return together only after a common multiple of 10 and 12 steps.

04 · How does the tenth item counted from Jia-Zi differ from moving ten steps from Jia-Zi?

Reference explanation

Counting Jia-Zi as item one requires nine moves to reach item ten, Gui-You. Moving ten steps reaches position eleven, Jia-Xu. Establish the counting convention before applying a rule.

Record the starting pair, position, step count, counting convention and result. This lab handles sequence relations; converting an actual date also requires a calendar, a reference date and boundary conventions.

Check the reference: Hong Kong Observatory, Table 2 ↗

Sequence checked 2026-10-24. Calculations, interaction and exercises are editorial teaching material; they do not calculate civil dates or natal charts.

Next: calendars and solar terms →

Personal study record; not a grade, assessment or credential.

Connected study paths

Calendars: cycles, terms and boundariesCosmic boards: objects and procedures

Editorial study material · 2026-10-24