diff --git a/SVSim.Database/Services/RankProgress/IRankProgressService.cs b/SVSim.Database/Services/RankProgress/IRankProgressService.cs
index 567ead6a..20125ff0 100644
--- a/SVSim.Database/Services/RankProgress/IRankProgressService.cs
+++ b/SVSim.Database/Services/RankProgress/IRankProgressService.cs
@@ -4,9 +4,13 @@ using SVSim.Database.Models;
 namespace SVSim.Database.Services.RankProgress;
 
 /// <summary>
-/// Wire-shape result of a single rank-battle finish grant. All fields map 1:1 to
-/// <c>RankBattleFinishResponseDto</c> keys the client reads via GetValueOrDefault
-/// in Wizard/RankBattleFinishTask.cs:57-63.
+/// Wire-shape result of a single rank-battle finish grant. The wire-mapped fields
+/// (<see cref="Rank"/>, <see cref="AfterBattlePoint"/>, <see cref="AfterMasterPoint"/>,
+/// <see cref="BattlePoint"/>, <see cref="MasterPoint"/>, <see cref="IsMasterRank"/>,
+/// <see cref="IsGrandMasterRank"/>) map 1:1 to <c>RankBattleFinishResponseDto</c>
+/// keys the client reads via GetValueOrDefault in Wizard/RankBattleFinishTask.cs:57-63.
+/// <see cref="TierAdvanced"/> is a controller-side signal for the rank_achieved mission
+/// emit and is not serialized to the wire.
 /// </summary>
 /// <param name="Rank">rank_id post-grant (1..29).</param>
 /// <param name="AfterBattlePoint">Point post-grant (accumulated).</param>
@@ -15,6 +19,10 @@ namespace SVSim.Database.Services.RankProgress;
 /// <param name="MasterPoint">Signed MasterPoint delta.</param>
 /// <param name="IsMasterRank">True iff Rank == 25.</param>
 /// <param name="IsGrandMasterRank">True iff Rank &gt;= 26.</param>
+/// <param name="TierAdvanced">
+/// True iff this grant crossed the viewer into a higher <see cref="RankTier"/> bucket
+/// than they held pre-grant. Callsites gate rank_achieved mission emits on this flag.
+/// </param>
 public sealed record RankProgressResult(
     int Rank,
     int AfterBattlePoint,
@@ -22,7 +30,8 @@ public sealed record RankProgressResult(
     int BattlePoint,
     int MasterPoint,
     bool IsMasterRank,
-    bool IsGrandMasterRank);
+    bool IsGrandMasterRank,
+    bool TierAdvanced = false);
 
 public interface IRankProgressService
 {
diff --git a/SVSim.Database/Services/RankProgress/RankProgressService.cs b/SVSim.Database/Services/RankProgress/RankProgressService.cs
index cc0fcac1..06322985 100644
--- a/SVSim.Database/Services/RankProgress/RankProgressService.cs
+++ b/SVSim.Database/Services/RankProgress/RankProgressService.cs
@@ -39,6 +39,9 @@ public sealed class RankProgressService : IRankProgressService
             viewer.RankProgress.Add(row);
         }
 
+        // Snapshot pre-tier for the TierAdvanced signal — compared to post-tier below.
+        string? preTier = RankTier.Name(CurrentRankId(row, byId));
+
         int deltaPoint = 0;
         int deltaMp = 0;
         int masterFloor = byId[MasterRankId].LowerLimitPoint; // 50000
@@ -81,6 +84,12 @@ public sealed class RankProgressService : IRankProgressService
         }
 
         int finalRank = CurrentRankId(row, byId);
+        string? postTier = RankTier.Name(finalRank);
+        // Tier "advanced" only on a promotion (pre != post AND both resolve). Demotion by
+        // point loss would technically change the tier string too, but rank_achieved is
+        // an achievement — it doesn't fire on going backward.
+        bool tierAdvanced = isWin && preTier != postTier && postTier is not null && preTier is not null;
+
         return new RankProgressResult(
             Rank:              finalRank,
             AfterBattlePoint:  row.Point,
@@ -88,7 +97,8 @@ public sealed class RankProgressService : IRankProgressService
             BattlePoint:       deltaPoint,
             MasterPoint:       deltaMp,
             IsMasterRank:      finalRank == MasterRankId,
-            IsGrandMasterRank: finalRank >= FirstGrandMasterRankId);
+            IsGrandMasterRank: finalRank >= FirstGrandMasterRankId,
+            TierAdvanced:      tierAdvanced);
     }
 
     public async Task<RankProgressResult> GetAsync(
diff --git a/SVSim.UnitTests/Services/RankProgressServiceTests.cs b/SVSim.UnitTests/Services/RankProgressServiceTests.cs
index ef1b0d62..e7812165 100644
--- a/SVSim.UnitTests/Services/RankProgressServiceTests.cs
+++ b/SVSim.UnitTests/Services/RankProgressServiceTests.cs
@@ -242,4 +242,45 @@ public class RankProgressServiceTests
         Assert.That(r.AfterMasterPoint, Is.EqualTo(0));
         Assert.That(v.RankProgress, Is.Empty);
     }
+
+    // ---- TierAdvanced ----
+
+    [Test]
+    public async Task TierAdvanced_is_false_when_win_stays_within_same_tier()
+    {
+        // Point 100 (Beginner 1, rank 2) + 100 win = 200 (Beginner 3, rank 4). Still beginner.
+        var svc = NewService();
+        var v = NewViewer(Format.Rotation, point: 100, masterPoint: 0);
+
+        var r = await svc.GrantAsync(v, Format.Rotation, isWin: true);
+
+        Assert.That(RankTier.Name(r.Rank), Is.EqualTo("beginner"));
+        Assert.That(r.TierAdvanced, Is.False);
+    }
+
+    [Test]
+    public async Task TierAdvanced_is_true_when_win_crosses_beginner_to_d()
+    {
+        // Point 1150 (Beginner 3, rank 4 — needs 1200 to leave beginner) + 100 = 1250 = D0 (rank 5).
+        var svc = NewService();
+        var v = NewViewer(Format.Rotation, point: 1150, masterPoint: 0);
+
+        var r = await svc.GrantAsync(v, Format.Rotation, isWin: true);
+
+        Assert.That(r.Rank, Is.EqualTo(5), "Expected promotion to rank 5 (D0)");
+        Assert.That(r.TierAdvanced, Is.True);
+    }
+
+    [Test]
+    public async Task TierAdvanced_is_false_on_loss_even_if_tier_string_changes()
+    {
+        // Loss can't advance a tier — even if it demoted, the achievement doesn't fire backward.
+        // Point 1200 (D0, rank 5) - 50 loss = 1200 (floored). Still D0. Prove flag stays false.
+        var svc = NewService();
+        var v = NewViewer(Format.Rotation, point: 1200, masterPoint: 0);
+
+        var r = await svc.GrantAsync(v, Format.Rotation, isWin: false);
+
+        Assert.That(r.TierAdvanced, Is.False);
+    }
 }