diff --git a/LICENSE.md b/LICENSE.md
index 1e4cab6..731cf7d 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -7,8 +7,9 @@ This program is distributed in the hope that it will be useful, but WITHOUT ANY
 
 You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-This program uses the following third party assets:
+This program uses the following third party assets and content:
 
 * Diplomacy Adjudicator Test Cases: Copyright (C) 2001-2024 Lucas B. Kruijswijk
 * Diplomacy standard map: Creative Commons BY-SA 3.0 Copyright (C) 2009 Martin Asal
+* Multiversal Diplomacy Adjudicator Test Cases: GNU General Public License v3.0 Copyright (C) 2022-2024 Tim Van Baak
 * The Time Machinations: Copyright (C) 2024 Matthew Pickard, AKA Lady Razor
\ No newline at end of file
diff --git a/server/Adjudication/Execution/Executor.cs b/server/Adjudication/Execution/Executor.cs
index 1f8d698..882f32f 100644
--- a/server/Adjudication/Execution/Executor.cs
+++ b/server/Adjudication/Execution/Executor.cs
@@ -80,7 +80,7 @@ private Board AdvanceMajorBoard(Board previousBoard)
             && previousBoard.Contains(o.Location)
             && !originalRetreatingUnits.Contains(o.Unit!));
         var incomingMoves = world.Orders.OfType<Move>().Where(m =>
-            m.Status == OrderStatus.Success || m.Status == OrderStatus.Retreat
+            (m.Status == OrderStatus.Success || m.Status == OrderStatus.Retreat)
             && previousBoard.Contains(m.Destination));
 
         var units = new List<Unit>();
diff --git a/server/Adjudication/Validation/AdjacencyValidator.cs b/server/Adjudication/Validation/AdjacencyValidator.cs
index d1df988..d752756 100644
--- a/server/Adjudication/Validation/AdjacencyValidator.cs
+++ b/server/Adjudication/Validation/AdjacencyValidator.cs
@@ -59,6 +59,11 @@ public bool IsValidIntraBoardMove(Unit unit, Location location, Location destina
             return false;
         }
 
+        if (location.RegionId == destination.RegionId)
+        {
+            return true;
+        }
+
         var locationRegion = regions.First(r => r.Id == location.RegionId);
         var destinationRegion = regions.First(r => r.Id == destination.RegionId);
 
diff --git a/server/Tests/MDATC_A.cs b/server/Tests/MDATC_A.cs
new file mode 100644
index 0000000..e88506c
--- /dev/null
+++ b/server/Tests/MDATC_A.cs
@@ -0,0 +1,291 @@
+using Adjudication;
+using Entities;
+using Enums;
+using FluentAssertions;
+using System.Diagnostics.CodeAnalysis;
+using Xunit;
+
+namespace Tests;
+
+// Adapted and extended from Multiversal Diplomacy Adjudicator Test Cases, Tim Van Baak
+// https://github.com/Jaculabilis/5dplomacy/blob/master/MDATC.html
+
+[SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores")]
+public class MDATC_A : AdjudicationTestBase
+{
+    [Fact(DisplayName = "A.01. Move to same region with loose adjacencies")]
+    public void MDATC_A_1()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = topBoard.AddUnits([(Nation.England, UnitType.Army, "Lon")]);
+
+        var order = units.Get("Lon").Move("Lon", timeline: 2);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Success);
+
+        topBoard.Next().ShouldHaveUnits([]);
+        bottomBoard.Next().ShouldHaveUnits([(Nation.England, UnitType.Army, "Lon", false)]);
+    }
+
+    [Fact(DisplayName = "A.02. Move to same region with strict adjacencies")]
+    public void MDATC_A_2()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = topBoard.AddUnits([(Nation.Turkey, UnitType.Fleet, "Smy")]);
+
+        var order = units.Get("Smy").Move("Smy", timeline: 2);
+
+        // Act
+        new Adjudicator(world, true, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Success);
+
+        topBoard.Next().ShouldHaveUnits([]);
+        bottomBoard.Next().ShouldHaveUnits([(Nation.Turkey, UnitType.Fleet, "Smy", false)]);
+    }
+
+    [Fact(DisplayName = "A.03. Move to neighbouring region with loose adjacencies")]
+    public void MDATC_A_3()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = bottomBoard.AddUnits([(Nation.Austria, UnitType.Army, "Vie")]);
+
+        var order = units.Get("Vie", timeline: 2).Move("Bud");
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Success);
+
+        topBoard.Next().ShouldHaveUnits([(Nation.Austria, UnitType.Army, "Bud", false)]);
+        bottomBoard.Next().ShouldHaveUnits([]);
+    }
+
+    [Fact(DisplayName = "A.04. Move to neighbouring region with strict adjacencies")]
+    public void MDATC_A_4()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = bottomBoard.AddUnits([(Nation.Italy, UnitType.Fleet, "Tun")]);
+
+        var order = units.Get("Tun", timeline: 2).Move("WES");
+
+        // Act
+        new Adjudicator(world, true, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        topBoard.Next().ShouldHaveUnits([]);
+        bottomBoard.Next().ShouldHaveUnits([(Nation.Italy, UnitType.Fleet, "Tun", false)]);
+    }
+
+    [Fact(DisplayName = "A.05. Move to non-neighbouring region")]
+    public void MDATC_A_5()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = topBoard.AddUnits([(Nation.England, UnitType.Fleet, "Lvp")]);
+
+        var order = units.Get("Lvp").Move("Edi", timeline: 2);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        topBoard.Next().ShouldHaveUnits([(Nation.England, UnitType.Fleet, "Lvp", false)]);
+        bottomBoard.Next().ShouldHaveUnits([]);
+    }
+
+    [Fact(DisplayName = "A.06. Can't cross coasts across time")]
+    public void MDATC_A_6()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = bottomBoard.AddUnits([(Nation.France, UnitType.Fleet, "Spa_S")]);
+
+        var order = units.Get("Spa_S", timeline: 2).Move("Spa_N");
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        topBoard.Next().ShouldHaveUnits([]);
+        bottomBoard.Next().ShouldHaveUnits([(Nation.France, UnitType.Fleet, "Spa_S", false)]);
+    }
+
+    [Fact(DisplayName = "A.07. No diagonal board movement")]
+    public void MDATC_A_7()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard(phase: Phase.Fall);
+        var bottomBoard = world.AddBoard(timeline: 2);
+
+        var units = topBoard.AddUnits([(Nation.Germany, UnitType.Army, "Mun")]);
+
+        var order = units.Get("Mun", phase: Phase.Fall).Move("Mun", timeline: 2);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        topBoard.Next().ShouldHaveUnits([(Nation.Germany, UnitType.Army, "Mun", false)]);
+        bottomBoard.Next().ShouldHaveUnits([]);
+    }
+
+    [Fact(DisplayName = "A.08. Must be adjacent timeline without convoy")]
+    public void MDATC_A_8()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard();
+        var middleBoard = world.AddBoard(timeline: 2);
+        var bottomBoard = world.AddBoard(timeline: 3);
+
+        var units = topBoard.AddUnits([(Nation.England, UnitType.Army, "Lon")]);
+
+        var order = units.Get("Lon").Move("Lon", timeline: 3);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        topBoard.Next().ShouldHaveUnits([(Nation.England, UnitType.Army, "Lon", false)]);
+        middleBoard.Next().ShouldHaveUnits([]);
+        bottomBoard.Next().ShouldHaveUnits([]);
+    }
+
+    [Fact(DisplayName = "A.09. Must be immediate past major board without convoy")]
+    public void MDATC_A_9()
+    {
+        // Arrange
+        var world = new World();
+
+        var presentBoard = world.AddBoard(year: 1902);
+        var pastBoard1 = world.AddBoard(phase: Phase.Winter);
+        var pastBoard2 = world.AddBoard(phase: Phase.Fall);
+        var pastBoard3 = world.AddBoard();
+
+        var units = presentBoard.AddUnits(
+            [
+                (Nation.England, UnitType.Army, "Lon"),
+                (Nation.France, UnitType.Army, "Par"),
+            ]);
+
+        var englishMove = units.Get("Lon", year: 1902).Move("Lon");
+        var frenchMove = units.Get("Par", year: 1902).Move("Gas", phase: Phase.Fall);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        englishMove.Status.Should().Be(OrderStatus.Invalid);
+        frenchMove.Status.Should().Be(OrderStatus.Success);
+
+        presentBoard.Next().ShouldHaveUnits([(Nation.England, UnitType.Army, "Lon", false)]);
+        pastBoard1.ShouldNotHaveNextBoard(timeline: 2);
+        pastBoard2.Next(timeline: 2).ShouldHaveUnits([(Nation.France, UnitType.Army, "Gas", false)]);
+        pastBoard3.ShouldNotHaveNextBoard(timeline: 2);
+    }
+
+    [Fact(DisplayName = "A.10. No move to winter board")]
+    public void MDATC_A_10()
+    {
+        // Arrange
+        var world = new World();
+
+        var presentBoard = world.AddBoard(year: 1902);
+        var pastBoard = world.AddBoard(phase: Phase.Winter);
+
+        presentBoard.AddCentres([(Nation.Russia, "Sev")]);
+        pastBoard.AddCentres([(Nation.Russia, "Sev")]);
+
+        List<Unit> units =
+            [
+                .. pastBoard.AddUnits([(Nation.Russia, UnitType.Fleet, "Sev")]),
+                .. presentBoard.AddUnits([(Nation.Russia, UnitType.Fleet, "Sev")]
+            )];
+
+        var order = units.Get("Sev", year: 1902).Move("Sev", phase: Phase.Winter);
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        order.Status.Should().Be(OrderStatus.Invalid);
+
+        presentBoard.Next().ShouldHaveUnits([(Nation.Russia, UnitType.Fleet, "Sev", false)]);
+        pastBoard.ShouldNotHaveNextBoard(timeline: 2);
+    }
+
+    [Fact(DisplayName = "A.11. Simultaneous adjustment and movement phases advance together")]
+    public void MDATC_A_11()
+    {
+        // Arrange
+        var world = new World();
+
+        var topBoard = world.AddBoard(year: 1902);
+        var bottomBoard = world.AddBoard(timeline: 2, phase: Phase.Winter);
+
+        bottomBoard.AddCentres([(Nation.Germany, "Ber")]);
+
+        var units = topBoard.AddUnits([(Nation.England, UnitType.Fleet, "Edi")]);
+
+        var englishMove = units.Get("Edi", year: 1902).Move("Cly", year: 1902);
+        var germanBuild = bottomBoard.Build(Nation.Germany, UnitType.Army, "Ber");
+
+        // Act
+        new Adjudicator(world, false, MapFactory, DefaultWorldFactory).Adjudicate();
+
+        // Assert
+        englishMove.Status.Should().Be(OrderStatus.Success);
+        germanBuild.Status.Should().Be(OrderStatus.Success);
+
+        topBoard.Next().ShouldHaveUnits([(Nation.England, UnitType.Fleet, "Cly", false)]);
+        bottomBoard.Next().ShouldHaveUnits([(Nation.Germany, UnitType.Army, "Ber", false)]);
+    }
+}