diff --git a/README.md b/README.md
index 125aa79..03ed0fa 100644
--- a/README.md
+++ b/README.md
@@ -66,14 +66,14 @@ Inputs:
 - `min_area_ratio`: Removes tiny disconnected components before grouping and matching, with `0.01` step precision. Default is `0.01`; `0.0` disables filtering. Values are relative to the largest disconnected component in the same input group, so `0.02` removes components smaller than 2% of that largest component's foreground area.
 - `rows`: Number of equal-height bbox grid rows. Default is `4`.
 - `columns`: Number of equal-width bbox grid columns. Default is `1`.
-- `auto_match_orientation`: Automatically swaps `rows` and `columns` for horizontal `mask1` product bboxes. Default is enabled.
+- `auto_match_orientation`: Automatically makes the longer split direction follow the longer side of the `mask1` product bbox. Default is enabled.
 
 Outputs:
 
 - `mask1`: First sliced/grouped mask batch.
 - `mask2`: Second mask batch aligned to `mask1`. When only one input is connected, this is an empty placeholder batch.
 
-The node splits disconnected painted islands internally, removes components below `min_area_ratio`, unions the remaining regions into one product mask, and slices that product bbox into a row-major grid: top to bottom, left to right. When `auto_match_orientation` is enabled, `rows=4, columns=1` stays 4x1 for vertical products and becomes 1x4 for horizontal products. In `mask` mode, empty `mask1` cells are skipped and `mask2` keeps the same remaining cell positions. In `bbox` mode, the full `rows × columns` rectangular grid is preserved. Use multiple rows and columns for two-dimensional local regions.
+The node splits disconnected painted islands internally, removes components below `min_area_ratio`, unions the remaining regions into one product mask, and slices that product bbox into a row-major grid: top to bottom, left to right. When `auto_match_orientation` is enabled, the larger of `rows` and `columns` follows the longer side of the product bbox: `rows=4, columns=1` stays 4x1 for vertical products and becomes 1x4 for horizontal products, while `rows=1, columns=3` becomes 3x1 for vertical products and stays 1x3 for horizontal products. In `mask` mode, empty `mask1` cells are skipped and `mask2` keeps the same remaining cell positions. In `bbox` mode, the full `rows × columns` rectangular grid is preserved. Use multiple rows and columns for two-dimensional local regions.
 
 ### RefineNode Match Product Angle
 
diff --git a/nodes.py b/nodes.py
index 73611fa..e9c41c6 100644
--- a/nodes.py
+++ b/nodes.py
@@ -522,8 +522,13 @@ def slice_masks_by_product_bbox(
     if mask1_bbox is None:
         return ([Image.new("L", mask1_size, 0)], [Image.new("L", mask2_size, 0)])
 
-    if auto_match_orientation and (mask1_bbox[2] - mask1_bbox[0]) > (mask1_bbox[3] - mask1_bbox[1]):
-        rows, columns = columns, rows
+    if auto_match_orientation and rows != columns:
+        long_count = max(rows, columns)
+        short_count = min(rows, columns)
+        if (mask1_bbox[2] - mask1_bbox[0]) > (mask1_bbox[3] - mask1_bbox[1]):
+            rows, columns = short_count, long_count
+        else:
+            rows, columns = long_count, short_count
 
     cells = normalized_grid_cells(rows, columns)