diff --git a/fsharp/ygosim/src/Board.fs b/fsharp/ygosim/src/Board.fs
index a07f5ff..d1ee869 100644
--- a/fsharp/ygosim/src/Board.fs
+++ b/fsharp/ygosim/src/Board.fs
@@ -132,8 +132,6 @@ module Board =
 module Client =
     open Player
     open Turn
-    open Card.Card
-    open Board
 
     type Log =
         | CardToHand of string
@@ -156,16 +154,24 @@ module Zone =
     open Side
 
     let freeMonsterZones player = List.filter Option.isNone player.side.monsters
-    let freeMonsterZoneCount player = List.length <| freeMonsterZones player
-    let hasFreeMonsterZones player count = freeMonsterZoneCount player >= count
+    let freeMonsterZoneCount = freeMonsterZones >> List.length
+    let hasFreeMonsterZones = (>=) << freeMonsterZoneCount
     let hasFreeMonsterZone player = hasFreeMonsterZones player 1
 
 module Summon =
+    open Card.Card
     open Board
     open Zone
     open Client
 
     module Normal =
+        let inline numberOfTributes monster =
+            let level = monster ^. Card.level
+
+            if level <= 4 then 0
+            elif level <= 6 then 1
+            else 2
+
         let canNormalSummon board =
             hasFreeMonsterZone <| board ^. Board.currentPlayer
             && board ^. Board.currentPlayerLastNormalSummon < board ^. Board.turn
@@ -181,6 +187,7 @@ module Summon =
 
             let turn = board ^. Board.turn
 
+
             board |> Board.currentPlayerLastNormalSummon .-> turn
 
 
diff --git a/fsharp/ygosim/src/Card.fs b/fsharp/ygosim/src/Card.fs
index 29dbaad..2363d75 100644
--- a/fsharp/ygosim/src/Card.fs
+++ b/fsharp/ygosim/src/Card.fs
@@ -116,9 +116,10 @@ module Card =
         let inline attribute f card = f card.attribute <&> fun v -> { card with attribute = v }
         let inline level f card = f card.level <&> fun v -> { card with level = v }
 
+    type Monster<'s> = BaseCard<'s> * MonsterCardDetails
 
     type Card<'s> =
-        | Monster of BaseCard<'s> * MonsterCardDetails
+        | Monster of Monster<'s>
         | Spell of BaseCard<'s> * SpellCardDetails
         | Trap of BaseCard<'s> * TrapCardDetails
 
@@ -126,6 +127,8 @@ module Card =
         let inline baseCard f card = _1 f card
         let inline cardDetails f card = _2 f card
 
+        let inline level f card = (_2 << MonsterCardDetails.level) f card
+
     type CardInstance<'s> = Card<'s>
 
 module Decklist =