Shift Calendar

The Shift Calendar is not a calendar (proposal) by itself, but a supplementary concept that is compatible with any calendar that has 91-day, i.e. 13-week quarters arranged in 3 months of 30 days twice and 31 days once or 3 months of 30 days and 1 extra day outside the month cycle. It works well with leap-week calendars, but probably better with leap-day calendars. The idea is to define several shift plans and work week independent of the actual 7-day week, but fixed to the calendar, cf. market weeks and Indonesian pawukon.

There are 5 cycles of 6 days called hexads and, likewise, 6 cycles of 5 days, pentads, per month. In months 31 days long, the final day is a holiday. Leap days and weeks and intercalary days are treated like holidays. Every hexad can also be subdivided into 2 sub-cycles of 3 days each, i.e. triads. Each cycle, whether 3, 5 or 6 days long, has one free day, which alternates among shift groups. There are also 3 larger cycles of 10 days per month, named decads, where each includes 3 days off. A half month of 3 pentads or 5 triads is called a crescent.

An integer number of cycles with 9 days, termed nonads, or 18 days fit well into the 90 regular days of a quarter, but they do not align with the cycles mentioned above inside 30-day months.

Normal 7-day weeks and 13-day cycles are the only ones which complete the 91 days of a quarter without holiday.

Quarter layout (with holiday at the end)

Triad	3	T01			T02			T03			T04			T05			T06			T07			T08			T09			T10			T11			T12			T13			T14			T15			T16			T17			T18			T19			T20			T21			T22			T23			T24			T25			T26			T27			T28			T29			T30			H
		1T0			1T1			1T2			1T3			1T4			1T5			1T6			1T7			1T8			1T9			2T0			2T1			2T2			2T3			2T4			2T5			2T6			2T7			2T8			2T9			3T0			3T1			3T2			3T3			3T4			3T5			3T6			3T7			3T8			3T9			H
Pentad	5	P01					P02					P03					P04					P05					P06					P07					P08					P09					P10					P11					P12					P13					P14					P15					P16					P17					P18					H
		1P1					1P2					1P3					1P4					1P5					1P6					2P1					2P2					2P3					2P4					2P5					2P6					3P1					3P2					3P3					3P4					3P5					3P6					H
Hexad	6	H01						H02						H03						H04						H05						H06						H07						H08						H09						H10						H11						H12						H13						H14						H15						H
		1H1						1H2						1H3						1H4						1H5						2H1						2H2						2H3						2H4						2H5						3H1						3H2						3H3						3H4						3H5						H
Decad	10	D1										D2										D3										D4										D5										D6										D7										D8										D9										H
		1D1										1D2										1D3										2D1										2D2										2D3										3D1										3D2										3D3										H
Crescent	15	C1															C2															C3															C4															C5															C6															H
		1C1															1C2															2C1															2C2															3C1															3C2															H
Month	30	M1																														M2																														M3																														H
Nonad	9	N0									N1									N2									N3									N4									N5									N6									N7									N8									N9									H
	18	E1																		E2																		E3																		E4																		E5																		H
Week	7	W01							W02							W03							W04							W05							W06							W07							W08							W09							W10							W11							W12							W13
	13	S1													S2													S3													S4													S5													S6													S7