---
type: Index
title: "Schools & Conventions (流派)"
description: "Where Palm Sutra schools differ in turning a birth date into a chart — late Zi and leap months."
resource: https://localpapa.com/tools/yizhang.html
tags: [yizhang, palm-sutra, schools, conventions]
timestamp: 2026-06-21T00:00:00Z
---

# Schools & Conventions · 流派

The Palm Sutra is interpretive, and schools differ — most concretely in **how a birth date is turned into the four pillars**. Two choices actually change the chart: the **late-Zi day boundary** and **leap-month assignment**. The [reading tool](https://localpapa.com/tools/yizhang.html) exposes both, defaulting to the common usage.

- [子時換日 (Zi-hour day boundary)](./zi.md) — The Palm Sutra fixes the Day pillar from the lunar day.
- [閏月歸月 (Leap-month assignment)](./leap.md) — A leap month sits between a month and the next; schools differ on which month a leap-month birth is charted under.
- [大限起法 (Decade-luck start)](./daxian.md) — Classical Palm Sutra texts read the four pillars; decade luck (大限) is a later addition and schools do not agree on it — whether to start from the Year or the Hour pillar, and whether direction depends on sex.
- [流月／流日起法 (Monthly & daily star method)](./liuri.md) — The Palm Sutra has a common method for the year (the year’s branch fixes the year star); for the **month and the day it has none**.

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*[The four pillars](../pillars/index.md) · [Palm Sutra knowledge base](../index.md)*