diff --git a/minimap2.1 b/minimap2.1
index 0cdf6d8a..1d0c1461 100644
--- a/minimap2.1
+++ b/minimap2.1
@@ -497,7 +497,7 @@ Up to 10% sequence divergence.
 .B asm20
 Long assembly to reference mapping
 .RB ( -k19
-.B -w10 -A1 -B6 -O6,26 -E2,1 -s200 -z200
+.B -w10 -A1 -B4 -O6,26 -E2,1 -s200 -z200
 .BR --min-occ-floor=100 ).
 Up to 20% sequence divergence.
 .TP