Karmic nodes are errors of a past incarnation that a person is capable of repeating in the present one. The point of the calculation is not to name a fault, but to show where a repetition is most likely.
The logic is straightforward. The consequence is deferred: the act was committed in one life and comes back in the next, and the person meets it without remembering the cause. That is why it looks like a run of bad luck with no reason behind it, always in the same area of life.
The force of that return, in this system, depends on behaviour. If a person knowingly repeats the same error, the return comes in full. If the error is not repeated but its character is kept — the sharpness, the disregard, the habit of not reckoning with other people — the return is softer, but it still comes. If the behaviour has changed as well, the matter stays in the background and barely interferes with living.
The practical conclusion is single and not mystical: the node points to the area where a person has reason to be more attentive than most. Not to fear it, but to know about it.
The error of the past incarnation is whatever was broken most severely.
It is calculated from the day arcanum and the month arcanum as the absolute difference: OPV = |DT − MT|. The absolute value is needed because the system has no negative numbers — for someone born on 1 April the difference 1 − 4 would give −3, and no such arcanum exists. Zero in these calculations is always 22.
The area this concerns is material welfare: work, income, property. When the error is repeated, the difficulties gather here rather than in relationships or in health.