window — the opening that brings in light

boundary /pathA /pathB …
  window [AssetName] w:1650 h:1100 [at:…] [edge:…] [name:…] [sill:…]

A window is written one level of indentation under a boundary. How its position is written — the ratio and grid-reference forms of at, choosing a side with edge — follows exactly the same rules as a door.

Two things differ. A window is not passable, so it adds no edge to the graph koyu doors walks; a wall with nothing but windows is still a wall you cannot get through. And a window counts toward daylight.

Write both w and h

Attribute	Required	Meaning
w	yes	width in mm along the segment. A referenced asset may supply it
h	optional for form / required for daylight	height in mm

Without w, parse stops. Without h, check still comes back green — but the window drops out of the daylight count entirely, because window area is the sum of w × h over the windows that have an h.

koyu 1.0
name 窓の書き方
unit mm

grid X 0 6000
grid Y 0 4000
level L1 0 h:2700 slab:200

space /L1/a room X1..X2 Y1..Y2 name:居室 daylight:1
space /out exterior name:外部

boundary /L1/a /out t:150 edge:S
  window w:1650 h:1100 sill:900 name:腰窓
boundary /L1/a /out t:150 edge:N
  window w:2600 h:2200 name:掃き出し窓
boundary /L1/a /out t:150 edge:E
  door w:900 h:2100 name:出口
boundary /L1/a /out t:150 edge:W

✔ /L1/a	居室	window 7.54 m2 / floor 24.00 m2 = 1/3.2 (needs 1/7 ≈ 3.43 m2)

Drop h:1100 from the low window and the number falls from 7.54 to 5.72.

✔ /L1/a	居室	window 5.72 m2 / floor 24.00 m2 = 1/4.2 (needs 1/7 ≈ 3.43 m2) ⚠ windows without h: are not counted

koyu check stays green. What puts it into words is validation, under the rule daylight.unknown (caution).

⚠ [daylight.unknown] win.muro:line 9: Window area is not fully counted: /L1/a has a window without h: (write h: on it)

It does not say "there is not enough window"; it says "the count is not complete". The report is that the source does not carry enough to answer the question either way.

Sill height is not written — it is what aligning the head leaves behind

The head of an opening sits at the lintel height of 2000mm. A door rises from the floor to meet it; every other opening drops from it by its own height.

Written	z range of the opening (above FL)
window w:1650 h:1100	900 … 2000
window w:2600 h:2200	−200 … 2000
window w:1650 (no h)	800 … 2000 (default height 1200)

The 900mm sill on the first line is written nowhere. It is what 2000 − 1100 leaves. And as the second line shows, take h above the lintel height and the bottom of the opening falls below the floor. If you want a full-height window, choose h knowing that the difference from the lintel height is what does the work.

sill: is a carried attribute — it is in the ledger, but the core never reads it once. Write it and it travels into the canonical JSON for another tool to use. It moves no geometry. Change sill:900 to sill:400 in the example above and the window still runs 900 … 2000.

The daylight coefficient

light looks only at spaces with a region that carry daylight:1. Nothing is inferred from the type — write room or write bedroom, and without the declaration the space is out of scope.

Effective window area is discounted by what lies beyond the window.

What the window faces	Coefficient
the outside (type:exterior)	1.0
semi-outdoor with a space above it (under a balcony, under an eave)	0.7
semi-outdoor open to the sky (a garden, a top-floor balcony)	1.0
anything else (indoors to indoors)	0 — not counted

Whether a space is semi-outdoor, and whether it is covered from above, are both derived rather than declared. A space with a region that meets the outside across an open or air:1 boundary is semi-outdoor.

The judgement itself — effective window area ≥ floor area ÷ 7 — is passed by koyu validate under daylight.ratio (violation), not by check. It is a rough early warning with no correction factor applied, and it looks at neither use-class proportions nor which buildings the rule applies to. Where the 1/7 lands is decided by the author, in choosing where to write daylight:1.

Attribute tiers

Attribute	Tier
w h at edge hinge swing	structure
style name	interpreted
sill spec fire	carried

A window uses the same ledger as a door. hinge, swing and style may all be written, but as a window is not passable no arc is drawn. A key outside the ledger needs a namespace containing a dot (acme.glazing:low-e) or it is ATT03.

Diagnostics

The diagnostics are shared with the door: OPN01 through OPN08, VRT05, UID04. OPN03 (an opening on an open boundary) says the same thing it says for a door — no effect on passage — which for a window was never in question.

To look a code up by cause and cure, there is the list of diagnostic codes.

Neighbouring pages

• boundary — the relation a window sits on
• door — same rules for position; only this one is passable
• asset — putting the defaults of a window in one place
• koyu light — returns the daylight numbers
• koyu validate — passes the 1/7 judgement