diff --git a/server/gameserver/gridservice.cc b/server/gameserver/gridservice.cc
index 994c1ab..b935319 100644
--- a/server/gameserver/gridservice.cc
+++ b/server/gameserver/gridservice.cc
@@ -175,4 +175,65 @@ void GridService::ComputeDiff(int old_grid_id, int new_grid_id,
                               std::set<GridCell*>& dec_grid_list)
 {
     int diff_grid = new_grid_id - old_grid_id;
+    if (diff_grid == 1) {
+        Get369(new_grid_id, inc_grid_list);
+        Get147(old_grid_id, dec_grid_list);
+    } else if (diff_grid == -1) {
+        Get147(new_grid_id, inc_grid_list);
+        Get369(old_grid_id, dec_grid_list);
+    } else if (diff_grid == cell_count_per_row_) {
+        Get789(new_grid_id, inc_grid_list);
+        Get123(old_grid_id, dec_grid_list);
+    } else if (diff_grid + cell_count_per_row_ == 0) {
+        Get123(new_grid_id, inc_grid_list);
+        Get789(old_grid_id, dec_grid_list);
+    } else if (diff_grid + cell_count_per_row_ == 1) {
+        Get123(new_grid_id, inc_grid_list);
+        GetGridList(new_grid_id, 6, inc_grid_list);
+        GetGridList(new_grid_id, 9, inc_grid_list);
+
+        GetGridList(old_grid_id, 1, dec_grid_list);
+        GetGridList(old_grid_id, 4, dec_grid_list);
+        Get789(old_grid_id, dec_grid_list);
+    } else if (diff_grid + cell_count_per_row_ == -1) {
+        Get123(new_grid_id, inc_grid_list);
+        GetGridList(new_grid_id, 4, inc_grid_list);
+        GetGridList(new_grid_id, 7, inc_grid_list);
+
+        GetGridList(old_grid_id, 6, dec_grid_list);
+        GetGridList(old_grid_id, 9, dec_grid_list);
+        Get789(old_grid_id, dec_grid_list);
+    } else if (diff_grid == cell_count_per_row_ + 1) {
+        Get789(new_grid_id, inc_grid_list);
+        GetGridList(new_grid_id, 3, inc_grid_list);
+        GetGridList(new_grid_id, 6, inc_grid_list);
+
+        GetGridList(old_grid_id, 4, dec_grid_list);
+        GetGridList(old_grid_id, 7, dec_grid_list);
+        Get123(old_grid_id, dec_grid_list);
+    } else if (diff_grid == cell_count_per_row_ - 1) {
+        Get789(new_grid_id, inc_grid_list);
+        GetGridList(new_grid_id, 1, inc_grid_list);
+        GetGridList(new_grid_id, 4, inc_grid_list);
+
+        GetGridList(old_grid_id, 6, dec_grid_list);
+        GetGridList(old_grid_id, 9, dec_grid_list);
+        Get123(old_grid_id, dec_grid_list);
+    } else {
+        std::set<GridCell*> new_grid_list;
+        Get123456789(new_grid_id, new_grid_list);
+        for (auto& cell : new_grid_list) {
+            if (grid_list.find(cell) == grid_list.end()) {
+                inc_grid_list.insert(cell);
+            }
+        }
+        for (auto& cell : grid_list) {
+            if (new_grid_list.find(cell) == new_grid_list.end()) {
+                dec_grid_list.insert(cell);
+            }
+        }
+    }
+
+    grid_list.clear();
+    Get123456789(new_grid_id, grid_list);
 }