What This Is
A year that finishes a circuit the chart was already holding open. 三合 is the union of three branches into a single elemental bureau, built from the 长生, 帝旺, and 墓库 positions: 申子辰 forms the Water bureau, 寅午戌 the Fire bureau, 巳酉丑 the Metal bureau, 亥卯未 the Wood bureau. When a chart natally carries two of the three, it sits with the bureau two-thirds formed, waiting. The transit year that supplies the missing third completes it.
This is the strongest of the branch-combination events. When the bureau closes, the chart's elemental balance reorganizes around the completing element — qi concentrates, and the whole field of forces tilts toward that one element for the duration. The classics note that when the bureau forms in a transit year, the five elements gather and major movement follows.
When It Fires
It fires when the year branch is the exact third member of a 三合 trinity that the natal chart already half-holds. Two branches present from birth, the year arriving with the third, and the bureau locks. It is a relatively common event because two-of-three is a frequent natal arrangement, but its effect is large whenever it lands.
What It Changes
It concentrates the chart's energy into a single element. Where the ordinary year adds an influence at the margins, a completed bureau reorganizes the center: the new element becomes dominant, and everything the chart does that year runs through it. This is a year of consolidation and reorganization rather than scattered events — a gathering of force around one theme.
The magnitude is the point. A completed bureau is not a nudge; it is a structural shift in which element rules the chart for the stretch.
How To Read It
Read it by whether the completing element is one the chart welcomes or fears. Where the bureau's element is a favorable one, the concentration becomes a power year — wealth, career, and recognition gathering as the chart's strength pools into the element it most wanted. Where the element is unfavorable, the same concentration over-supplies what the chart already had too much of, and the over-concentration brings strain rather than gain.
So the bureau is a force-multiplier on a single element, and its meaning follows the chart's need. A welcome element completed is a year of consolidation and ascent; an unwelcome one completed is a year of imbalance pushed to excess. The reading is never the bureau alone — it is the bureau against what the chart was missing or already carried too much of.
Where This Shows Up
A period under a completed bureau feels like everything pulling in one direction. Scattered efforts converge; a single theme dominates work and circumstance; the year has a center of gravity it did not have before. When the element is favorable, it is often the year a long-building strength finally consolidates into result — resources gathering, a position solidifying, the chart operating at concentrated power.
When the element is unfavorable, the same gathering becomes too much of one thing — a flooding of an energy the chart could not use well, felt as pressure, imbalance, or a year where the dominant theme overwhelms rather than serves. The texture in both cases is concentration: a stretch organized around one element, for the chart's benefit or against it.