diff --git a/rating/src/main/scala/glicko/model.scala b/rating/src/main/scala/glicko/model.scala
index 154942154..1237ffb33 100644
--- a/rating/src/main/scala/glicko/model.scala
+++ b/rating/src/main/scala/glicko/model.scala
@@ -34,7 +34,7 @@ val cluelessDeviation    = 230
 
 case class Player(
     glicko: Glicko,
-    numberOfResults: Int,
+    numberOfResults: Int = 0,
     lastRatingPeriodEnd: Option[Instant] = None
 ):
   export glicko.*
diff --git a/test-kit/src/test/scala/rating/glicko/GlickoCalculatorWithColorAdvantageTest.scala b/test-kit/src/test/scala/rating/glicko/GlickoCalculatorWithColorAdvantageTest.scala
new file mode 100644
index 000000000..c63b271c8
--- /dev/null
+++ b/test-kit/src/test/scala/rating/glicko/GlickoCalculatorWithColorAdvantageTest.scala
@@ -0,0 +1,40 @@
+package chess
+package rating
+package glicko
+
+class GlickoCalculatorWithColorAdvantageTest extends ChessTest:
+
+  import Outcome.*
+
+  private def ratingDiff(r: Int, opRating: Int, outcome: Outcome, expected: Int)(using
+      munit.Location
+  ) =
+    val player = Player(Glicko(r, 1d, 1d))
+    val opponent = Player(Glicko(opRating, 1d, 1d))
+    val game   = Game(ByColor(player, opponent), outcome)
+    // TODO: calculator with color advantage
+    val calculator = GlickoCalculator()
+    calculator.computeGame(game)
+
+  test("new rating calculation over one game"):
+    ratingDiff(1500, 1500, white, 20)
+    ratingDiff(1500, 1500, black, -20)
+    ratingDiff(1500, 1500, draw, 0)
+    ratingDiff(1500, 1900, white, 37)
+    ratingDiff(1500, 1900, black, -3)
+    ratingDiff(1500, 1900, draw, 17)
+    ratingDiff(1500, 2900, white, 37)
+    ratingDiff(1500, 2900, black, -3)
+    ratingDiff(1500, 2900, draw, 17)
+    ratingDiff(1500, 1600, white, 26)
+    ratingDiff(1500, 1600, black, -14)
+    ratingDiff(1500, 1600, draw, 6)
+    ratingDiff(2000, 1600, white, 3)
+    ratingDiff(2000, 1600, black, -37)
+    ratingDiff(2000, 1600, draw, -17)
+    ratingDiff(2000, 1000, white, 3)
+    ratingDiff(2000, 1000, black, -37)
+    ratingDiff(2000, 1000, draw, -17)
+    ratingDiff(2000, 1900, white, 14)
+    ratingDiff(2000, 1900, black, -26)
+    ratingDiff(2000, 1900, draw, -6)