diff --git a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/api/PairingHandler.kt b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/api/PairingHandler.kt
index 4e6b07c..ef15003 100644
--- a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/api/PairingHandler.kt
+++ b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/api/PairingHandler.kt
@@ -73,6 +73,7 @@ object PairingHandler: PairgothApiHandler {
         }.toSet()
         game.black = payload.getID("b") ?: badRequest("missing black player id")
         game.white = payload.getID("w") ?: badRequest("missing white player id")
+        tournament.recomputeDUDD(round, game.id)
         // temporary
         payload.getInt("dudd")?.let { game.drawnUpDown = it }
         val black = tournament.pairables[game.black] ?: badRequest("invalid black player id")
diff --git a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/model/Tournament.kt b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/model/Tournament.kt
index 411f313..b380dd6 100644
--- a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/model/Tournament.kt
+++ b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/model/Tournament.kt
@@ -4,6 +4,8 @@ import com.republicate.kson.Json
 import com.republicate.kson.toJsonArray
 import kotlinx.datetime.LocalDate
 import org.jeudego.pairgoth.api.ApiHandler.Companion.badRequest
+import org.jeudego.pairgoth.pairing.solver.MacMahonSolver
+import org.jeudego.pairgoth.pairing.solver.SwissSolver
 import org.jeudego.pairgoth.store.Store
 import kotlin.math.roundToInt
 
@@ -65,6 +67,22 @@ sealed class Tournament <P: Pairable>(
         if (round > games.size + 1) throw Error("invalid round")
         else mutableMapOf<ID, Game>().also { games.add(it) }
     fun lastRound() = games.size
+
+    fun recomputeDUDD(round: Int, gameID: ID) {
+        // Instantiate solver with game history
+        // TODO cleaner solver instantiation
+        val history = games.map { games -> games.values.toList() }
+        val solver = when (pairing.type) {
+            PairingType.SWISS -> SwissSolver(round, history, pairables.values.toList(), pairing.pairingParams, pairing.placementParams)
+            PairingType.MAC_MAHON -> MacMahonSolver(round, history, pairables.values.toList(), pairing.pairingParams, pairing.placementParams, mmBar = 3, mmFloor = -20)
+            else -> throw Exception("Invalid tournament type")
+        }
+        // Recomputes DUDD
+        val game = games(round)[gameID]!!
+        val whiteplayer = solver.pairables.find { p-> p.id == game.white }!!
+        val blackplayer = solver.pairables.find { p-> p.id == game.black }!!
+        game.drawnUpDown = solver.dudd(blackplayer, whiteplayer)
+    }
 }
 
 // standard tournament of individuals
diff --git a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/pairing/solver/BaseSolver.kt b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/pairing/solver/BaseSolver.kt
index e21cfc5..f49d819 100644
--- a/api-webapp/src/main/kotlin/org/jeudego/pairgoth/pairing/solver/BaseSolver.kt
+++ b/api-webapp/src/main/kotlin/org/jeudego/pairgoth/pairing/solver/BaseSolver.kt
@@ -527,11 +527,14 @@ sealed class BaseSolver(
         return scale * (1.0 - x) * (1.0 + k * x)
     }
 
+    fun dudd(black: Pairable, white: Pairable): Int {
+        return white.group - black.group
+    }
     open fun games(black: Pairable, white: Pairable): List<Game> {
         // CB TODO team of individuals pairing
         val usedTables = tables.getOrNull(round - 1) ?: BitSet().also { tables.add(it) }
         val table = if (black.id == 0 || white.id == 0) 0 else usedTables.nextClearBit(1)
         usedTables.set(table)
-        return listOf(Game(id = Store.nextGameId, table = table, black = black.id, white = white.id, handicap = pairing.handicap.handicap(white, black), drawnUpDown = white.group-black.group))
+        return listOf(Game(id = Store.nextGameId, table = table, black = black.id, white = white.id, handicap = pairing.handicap.handicap(white, black), drawnUpDown = dudd(black, white)))
     }
 }