Lord of the House in Each House (Bonatti's 144-Cell Judgment Grid)
Definition
The lord-of-the-house-in-each-house technique is Bonatti's systematic enumeration for judging a chart house by house: he takes the lord of each of the twelve houses and walks it through each of the twelve places, yielding a 12-by-12 grid of one hundred forty-four cells. Each cell gives a concrete natal-or-horary verdict for that lord in that place — the lord of the seventh in the eighth signifying gain through someone's death, the lord of the first in the twelfth signifying imprisonment, chronic illness, or melancholia — modulated by which planet is the significator and whether it is a fortune or an infortune.
In Tradition
This is the systematic culmination of the Arabic per-house judgment tradition: the affairs of any house are read not only from that house but from where its lord lands among the twelve places, so that the whole chart is judged by tracing each house-lord through the wheel. Bonatti caps the grid with a methodological chapter defending the full twelve-house procedure against practitioners who judged only from the first and seventh houses, holding that complete enumeration gives surer signification.
In Practice
For the topic you are judging, identify the lord of the relevant house — the planet ruling the sign on that house — then locate which place that lord occupies, counting whole-sign from the Ascendant. Read the cell the pairing forms: the lord of the second in the third points to loss through neighbours, short journeys, or blood-relatives; the lord of the fourth in the sixth, in a universal question, to illness among a land's inhabitants; the lord of the fifth in the first, in a question about life, to a long and honourable life. Then modulate by the significator itself: read the affair as good when the planet is a fortune well placed, harmful when it is an infortune badly placed, and colour it by the planet's nature — Mars toward iron, fire, and strife, Venus toward women and free living, Jupiter toward judges and ecclesiastics. Use the full grid rather than the first and seventh houses alone, weighing the cell as one testimony within the chart's wider condition.
Historical Origin
The procedure is set out in Guido Bonatti's Liber Astronomiae (c. 1277, Tractate II, Second Part, Chapter VI), with the closing methodological chapter 'Concerning the Ease of Discovering the Signification of Each House.' The doctrine descends through the Arabic per-house judgment tradition — Sahl ibn Bishr, Masha'allah, and Abu Ma'shar — and is ultimately Dorothean. It is preserved in the Project Hindsight English edition translated by Robert Zoller and edited by Robert Hand.