HOUSE SYSTEMS
Koch
Koch is a time-based quadrant system tied to the birth latitude and the rising-time geometry of the Midheaven degree.
The idea in context
A time-based quadrant system using the birthplace latitude and the diurnal arc associated with the Midheaven to construct intermediate cusps.
MAKE IT CONCRETE
An example to picture
A planet near an intermediate cusp can fall in a different house than in Placidus even when the Ascendant and Midheaven agree.
How to read it
Compare the exact cusps instead of assuming two quadrant systems are interchangeable, particularly for placements close to a boundary.
A common misunderstanding
Koch can be undefined in polar regions. An unsupported result requires an explicit choice of another system, not a guessed cusp.
BRING IT BACK TO YOUR LIFE
A question to sit with
Does changing the cusp framework offer a useful alternative reading without changing the planet or its sign?
Go deeper: the full reference
How to read it
The Ascendant and Midheaven anchor the 1st and 10th cusps. Koch can place a planet in a different house from Placidus even though both use those same primary angles.
Input and calculation limits
Koch may be undefined at high latitudes. Synastry does not silently replace it with another house system when a calculation cannot be supported.
Compare one choice at a time
Changing the house system changes cusps and may change house assignments. It does not move the planets through the zodiac. These are interpretive frameworks, not measured personality traits or predictions. Private chart settings do not change dating compatibility.
Try reading your own birth chart
Create a free birth chart, select the placement or symbol you are learning about, and read it alongside this lesson. A planet’s sign, house and aspects add context; keep your recorded birth time and chart settings in view.
Connect the ideas
Placidus
A time-based quadrant system that divides the diurnal and nocturnal motion used to define intermediate house cusps. The Ascendant and Midheaven anchor the 1st and 10th cusps.
2 min readWhole Sign
The entire zodiac sign containing the Ascendant is the 1st House. Each following sign forms the next house, with cusps at sign boundaries.
2 min readEqual House
The exact Ascendant degree begins the 1st House, followed by eleven equal 30° sectors along the zodiac.
2 min readPorphyry
Each zodiacal arc between successive primary angles is divided into three equal portions to form the intermediate house cusps.
1 min read