diff --git a/contracts/Evaluator.cairo b/contracts/Evaluator.cairo
index 01337dd..cf8da0f 100644
--- a/contracts/Evaluator.cairo
+++ b/contracts/Evaluator.cairo
@@ -94,6 +94,9 @@ func read_ticker{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr
     player_address: felt
 ) -> (ticker: felt) {
     let (rank) = assigned_rank(player_address);
+    with_attr_error_message("No rank assigned via ex1_assign_rank. Maybe the transaction is pending?") {
+        assert_not_zero(rank);
+    }
     let (ticker) = random_attributes_storage.read(rank, 0);
     return (ticker,);
 }
@@ -103,6 +106,9 @@ func read_supply{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr
     player_address: felt
 ) -> (supply: Uint256) {
     let (rank) = assigned_rank(player_address);
+    with_attr_error_message("No rank assigned via ex1_assign_rank. Maybe the transaction is pending? ") {
+        assert_not_zero(rank);
+    }
     let (supply_felt) = random_attributes_storage.read(rank, 1);
     let supply: Uint256 = Uint256(supply_felt, 0);
     return (supply,);
@@ -122,6 +128,7 @@ func constructor{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr
     ex_initializer(_tuto_erc20_address, _players_registry, _workshop_id);
     dummy_token_address_storage.write(_dummy_token_address);
     teacher_accounts.write(_first_teacher, 1);
+    rank_storage.write(1); // 0 will be used to flag unassigned addresses
     // Hard coded value for now
     max_rank_storage.write(100);
     return ();
diff --git a/contracts/utils/ex00_base.cairo b/contracts/utils/ex00_base.cairo
index 3893b05..120d9b8 100644
--- a/contracts/utils/ex00_base.cairo
+++ b/contracts/utils/ex00_base.cairo
@@ -266,7 +266,7 @@ func assign_rank_to_player{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range
 
     // Checking if we reach max_rank
     if (new_next_rank == max_rank) {
-        next_rank_storage.write(0);
+        next_rank_storage.write(1);
     } else {
         next_rank_storage.write(new_next_rank);
     }