diff --git a/core/common/src/ArbitraryPrecisionDate.kt b/core/common/src/ArbitraryPrecisionDate.kt
new file mode 100644
index 000000000..68f37b244
--- /dev/null
+++ b/core/common/src/ArbitraryPrecisionDate.kt
@@ -0,0 +1,13 @@
+package kotlinx.datetime
+
+public sealed interface ArbitraryPrecisionDate : Comparable<ArbitraryPrecisionDate> {
+
+    public val year: Int
+
+    public companion object {
+
+        public fun parse(value: String): ArbitraryPrecisionDate {
+            TODO()
+        }
+    }
+}
diff --git a/core/common/src/Year.kt b/core/common/src/Year.kt
new file mode 100644
index 000000000..ff465c606
--- /dev/null
+++ b/core/common/src/Year.kt
@@ -0,0 +1,7 @@
+package kotlinx.datetime
+
+public data class Year(override val year: Int) : ArbitraryPrecisionDate {
+
+    override fun compareTo(other: ArbitraryPrecisionDate): Int =
+        year.compareTo(other.year)
+}
diff --git a/core/common/src/YearMonth.kt b/core/common/src/YearMonth.kt
new file mode 100644
index 000000000..5f1352999
--- /dev/null
+++ b/core/common/src/YearMonth.kt
@@ -0,0 +1,8 @@
+package kotlinx.datetime
+
+public data class YearMonth(override val year: Int, public val month: Month) : ArbitraryPrecisionDate {
+
+    override fun compareTo(other: ArbitraryPrecisionDate): Int {
+        TODO("Not yet implemented")
+    }
+}