1300

1 files changed, 8 insertions, 0 deletions

diff --git a/Add-a-new-map-and-landmark.md b/Add-a-new-map-and-landmark.md
index 966da9f..d6bb8de 100644
--- a/Add-a-new-map-and-landmark.md
+++ b/Add-a-new-map-and-landmark.md
@@ -53,6 +53,14 @@ Now create another new map, 9 blocks wide and 6 blocks high, using the `radio_to
 
 Save that as **maps/GlobalTerminal1F.blk**.
 
+When you're designing maps, keep their size below this limit:
+
+(*width* + 6) × (*height* + 6) ≤ 1300
+
+The current map's block data gets loaded into WRAM at the address `wOverworldMapBlocks`, which is declared to have 1300 bytes in [wram.asm](../blob/master/wram.asm). This buffer gets padded on all sides with an extra 3 blocks to load the edges of any connected maps.
+
+It so happens that a 30x30 map will neatly fit into this limit, since (30+6)×(30+6)=1296. However, keep in mind that the official maps are usually designed with the width as a multiple of 10 and the height as a multiple of 9. For example, small towns are often 10x9; large cities are 20x18; routes may be 20x9, or 10x18, or 10x45, or so on; National Park is 20x27; et cetera.
+
 
 ## 3. Define a map constant