Two charts, read against each other
The tradition calls this 合婚. It begins with one question that has nothing to do with sentiment: between these two Day Masters, which way does the traffic run.
Why the direction is settled first
Five phases taken two at a time give twenty-five ordered pairs, and each of them stands in exactly one of five relations: parity, you generate them, they generate you, you control them, they control you. Which relation holds is arithmetic, not judgement, and it is fixed before a word is said about how either person experiences it.
Order matters. A wood chart with a fire chart is not the same reading as a fire chart with a wood chart — one is the fuel and the other is the flame, and the tradition is unsentimental about what that costs the fuel. So the pages below are listed in both directions, twenty-five in all, and each is read from the first chart's side.
None of this ranks pairs. There is no good match and no bad match in the classical treatment; there is a direction, a price attached to it, and the observation that the price is structural rather than anybody's fault.
Cast the chart this page describes
The four pillars, the Day Master, the five-phase count, the day’s almanac read against the chart and the true solar time working — about 2,700 words — are free and need no account. The chart is computed in the browser; nothing about the birth is sent anywhere.