diff --git a/README.md b/README.md
index 80184e9..de40efc 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,7 @@ da = MS.new(
 |  | chan | Dimension | Channel ID | - | 0 | numpy.ndarray | (chan,) | int64 |
 | Labels | beam | Coordinate | Beam label | - | "" | numpy.ndarray | (time,) | str (<U16) |
 |  | scan | Coordinate | Scan label | - | "" | numpy.ndarray | (time,) | str (<U16) |
+|  | subscan | Coordinate | Sub-scan label | - | "" | numpy.ndarray | (time,) | str (<U16) |
 |  | state | Coordinate | State label | - | "" | numpy.ndarray | (time,) | str (<U16) |
 | Telescope pointing | lon | Coordinate | Sky longitude | deg | 0.0 | numpy.ndarray | (time,) | float64 |
 |  | lat | Coordinate | Sky latitude | deg | 0.0 | numpy.ndarray | (time,) | float64 |
diff --git a/dems/d2.py b/dems/d2.py
index 5de040e..c520567 100644
--- a/dems/d2.py
+++ b/dems/d2.py
@@ -81,6 +81,12 @@ class Scan:
     long_name: Attr[str] = "Scan label"
 
 
+@dataclass
+class Subscan:
+    data: Data[Ti, Literal["U16"]]
+    long_name: Attr[str] = "Sub-scan label"
+
+
 @dataclass
 class State:
     data: Data[Ti, Literal["U16"]]
@@ -355,6 +361,7 @@ class MS(AsDataArray):
     # labels
     beam: Coordof[Beam] = ""
     scan: Coordof[Scan] = ""
+    subscan: Coordof[Subscan] = ""
     state: Coordof[State] = ""
     # telescope pointing
     lon: Coordof[Lon] = 0.0