The starting point of the chart
Astrologers read this house as your starting point: appearance, physical energy, how you carry yourself, and the sort of reaction you tend to get from strangers. Planets here are hard to hide. Someone with Mars in the 1st may walk fast and look ready to disagree, even when they’re in a lovely mood. With Neptune here, people often can’t quite describe them afterward.
In love and dating
This house tends to shape the first few weeks more than the first few years. Your photos, your energy on a date, whether you come across as easy or guarded: that’s 1st house territory. It’s also the source of a common complaint, “people assume I’m confident,” or “people assume I’m cold,” from someone who feels nothing of the kind.
Between two charts, astrologers look at whether someone’s planet falls in your 1st house. It tends to make that person very aware of you, and they may start to influence how you see yourself.
How much the app uses houses
Honestly, not much. Houses come from your birth time and birthplace, so they aren’t known for everyone. In MatchMachine they play one modest part: planets in the 1st, 4th, 7th and 10th houses count as stronger, then the 2nd, 5th, 8th and 11th, then the 3rd, 6th, 9th and 12th. That strength gives a planet’s aspects a bit more room and helps decide which planet comes out strongest in your chart.
The app doesn’t give you a reading of “your Mars in the 1st,” and it won’t draw conclusions from it about who you’ll meet. The rest of this series is here because the houses are useful to think with, and because you’ll see them on any chart.