diff --git a/CHANGELOG.md b/CHANGELOG.md
index a370994..88aac51 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## Unreleased
+
+* Fixed an oversight where the default version tag pattern would only find
+  tags with exactly three parts in the base (e.g., `v1.0.0` and `v1.2.3`).
+  This is now relaxed so that `v1`, `v1.2.3.4`, and so on are also recognized.
+* Added support for execution via `python -m dunamai`.
+  ([Contributed by jstriebel](https://github.com/mtkennerly/dunamai/pull/19))
+
 ## v1.5.5 (2021-04-26)
 
 * Fixed handling of Git tags that contain slashes.
diff --git a/dunamai/__init__.py b/dunamai/__init__.py
index 254b1b2..cc22260 100644
--- a/dunamai/__init__.py
+++ b/dunamai/__init__.py
@@ -25,7 +25,7 @@
 
 _VERSION_PATTERN = r"""
     (?x)                                                (?# ignore whitespace)
-    ^v(?P<base>\d+\.\d+\.\d+)                           (?# v1.2.3)
+    ^v(?P<base>\d+(\.\d+)*)                             (?# v1.2.3)
     (-?((?P<stage>[a-zA-Z]+)\.?(?P<revision>\d+)?))?    (?# b0)
     (\+(?P<tagged_metadata>.+))?$                       (?# +linux)
 """.strip()
diff --git a/tests/unit/test_dunamai.py b/tests/unit/test_dunamai.py
index b8992d3..398e9f2 100644
--- a/tests/unit/test_dunamai.py
+++ b/tests/unit/test_dunamai.py
@@ -548,6 +548,9 @@ def check_re(
 
     check_re("v0.1.0rc.4+specifier", "0.1.0", "rc", "4", tagged_metadata="specifier")
 
+    check_re("v1", "1")
+    check_re("v1b2", "1", "b", "2")
+
 
 def test__serialize_pep440():
     assert serialize_pep440("1.2.3") == "1.2.3"