The Devil, the trump of Capricorn
Major Arcana XV · Hebrew letter Ayin · Earth, cardinal
Ayin is the Hebrew letter assigned to The Devil in Book T, forming part of the correspondence that links this trump with Capricorn. The letter functions as a connecting label within the system, rather than an explanation of your personality. You can use that link to examine attachment in Capricorn’s Earth concerns: the body, money, work, and material results.
As a cardinal sign, Capricorn initiates; here, the reading asks what happens when something you started becomes difficult to leave. You might accept a demanding job to build savings, then increase your spending until leaving feels unaffordable. The Devil is read as the dependency within that arrangement, prompting you to ask which commitments still serve you and which you now maintain at your own expense.
The Devil: upright, reversed, love and career →
The three decans of Capricorn
Capricorn is split into three parts of 10°, and each takes one of the Pentacles: the suit of Earth, numbered Two to Four for a cardinal sign. Each decan also has a planet, and its trump is worth reading alongside.

II♦︎
1st decan · 0°–10° · December 22–30 · ♃︎ Jupiter in Capricorn · Lord of Harmonious Change
Expansion needs somewhere practical to go: Jupiter in Capricorn is read as growth negotiated through available resources. In the Two of Pentacles, confidence takes the form of adjusting rather than assuming everything will fit. You might accept more work while rearranging your hours and expenses. The reading asks whether your juggling makes room for growth or merely keeps an overloaded schedule moving.
Planet card: Wheel of Fortune (Jupiter)

III♦︎
2nd decan · 10°–20° · December 31 – January 9 · ♂︎ Mars in Capricorn · Lord of Material Works
At a shared workbench, Mars in Capricorn is read as drive directed toward a material result. The Three of Pentacles brings that effort into collaboration, where skill has to be demonstrated and recognized by others. You might resolve a disagreement by showing how a task should be done. The question is whether your push advances the work while leaving room for other people’s expertise.
Planet card: The Tower (Mars)

IV♦︎
3rd decan · 20°–30° · January 10–19 · ☉︎ Sun in Capricorn · Lord of Earthly Power
What do you need to keep in order to feel established? Sun in Capricorn is read as the will to be seen taking material form, and the Four of Pentacles focuses that reading on what you hold. You might protect a savings balance so fiercely that every necessary expense feels like a threat. Consider where security supports your vitality and where maintaining control consumes it.
Planet card: The Sun (Sun)
The court card of Capricorn

Q♦︎
20° Sagittarius – 20° Capricorn · December 13 – January 9 · Water of Earth
Because the Queen of Pentacles begins her span in Sagittarius, her practical care need not be treated as an exclusively Capricorn role. Her reach into Capricorn lets you read that care alongside the sign’s impulse to initiate material work. You might organize a household budget around what people actually need, then put those priorities into practice. Her court-card coverage is partial, though: for Capricorn’s final third, the court reference is the King of Swords rather than the Queen.
The last 10° of Capricorn (January 10–19) belong to the King of Swords, which runs on to 20° Aquarius.