What a reversal is
A card that comes out upside down. That is all it is mechanically. What it means is a choice you make, and there are several defensible ones.
The four approaches
1. Opposite meaning. The Sun reversed becomes gloom. Simple, and the crudest. It throws away the card's actual content.
2. Blocked or internalised. The card's energy is present but obstructed, or turned inward rather than outward. The Sun reversed is joy that cannot get out. It is the most widely used approach, and it is the one the reversed meanings on every card page here assume.
3. Excess or deficiency. Too much of the card, or too little. The Emperor reversed is either tyranny or an authority vacuum. You decide which from the surrounding cards.
4. Shadow aspect. The card's difficult face. Strength reversed is not weakness but force.
Or: don't use them
A large number of professional readers read every card upright. Their argument is straightforward. Every card already contains its own difficulty, and the deck has enough hard cards without doubling the count. The Tower does not need a reversal to deliver bad news.
Where reversals came from
They are not ancient. The first clear instructions for reading inverted cards come from Etteilla in the late eighteenth century, at the point tarot was being turned from a card game into a divinatory system. Waite included reversed meanings in 1910 and most twentieth century books followed him, which is why they feel standard now.
Knowing this helps, because it tells you reversals are a convention rather than a property of the deck. Conventions can be adopted or declined. Nobody is doing it wrong.
How to get them, or avoid them
If you want reversals with a physical deck you have to introduce them deliberately: rotate half the pack occasionally, or cut and turn one half before shuffling. An ordinary riffle shuffle almost never inverts a card, which is why readers who shuffle neatly and use reversals often find they hardly appear.
Here you turn them on or off before you draw. With them on, each card is decided separately, so roughly half arrive inverted, the way a well shuffled physical deck behaves.
When a spread is full of them
Some readers panic at six reversals out of ten. Do not read them one at a time in that situation; read the weight itself.
A heavily reversed spread usually says one of two things. The situation is internal rather than external, happening inside you rather than in the world. Or the whole thing is stalled, and the question is what is blocking it rather than what is happening.
The same is true in the other direction. A spread with none at all, when you are using them, is a situation moving openly and outwardly.
The card that changes most
Worth knowing which cards actually turn on their orientation and which barely move.
Cards with a strong direction change a great deal. The Eight of Cups upright is walking away; reversed it is being unable to. The Chariot upright is control; reversed it is a vehicle with nobody steering.
Cards that are already about difficulty change less. The Tower reversed is still a collapse, perhaps delayed or resisted or smaller. Reading it as "no collapse" is where the opposite-meaning approach falls down badly.
What to actually do
Pick one approach and stay with it for at least three months. Consistency matters far more than which one you chose, because meaning accumulates through use. Switching methods every few weeks means you never build the fluency that makes readings feel fluent.
If you are starting today: read upright only. Add reversals when the upright meanings feel automatic.
There is one more argument for waiting. Seventy-eight cards is already a lot to hold. Using reversals from day one effectively asks you to learn one hundred and fifty-six, and the usual result is that both halves stay shallow. The upright meanings are the foundation; the reversed ones are a modification of something you need to know first.
