diff --git a/polkadot/node/primitives/src/lib.rs b/polkadot/node/primitives/src/lib.rs
index 7544dd8d72145d2a7bcd4868f4427e0b76a01b4a..6e8490b67b91c470f43997fa7cd7860f834905e4 100644
--- a/polkadot/node/primitives/src/lib.rs
+++ b/polkadot/node/primitives/src/lib.rs
@@ -69,8 +69,7 @@ pub const POV_BOMB_LIMIT: usize = (MAX_POV_SIZE * 4u32) as usize;
 /// On Polkadot this is 1 day, and on Kusama it's 6 hours.
 ///
 /// Number of sessions we want to consider in disputes.
-/// + 1 for the child's session.
-pub const DISPUTE_WINDOW: SessionIndex = 6 + 1;
+pub const DISPUTE_WINDOW: SessionIndex = 6;
 
 /// The cumulative weight of a block in a fork-choice rule.
 pub type BlockWeight = u32;
diff --git a/polkadot/node/subsystem-util/src/rolling_session_window.rs b/polkadot/node/subsystem-util/src/rolling_session_window.rs
index 1c73ff58c7181100647a449e76c1954681b045bd..fc2957b7ea23450559bd5f77052e4c3f5cd63436 100644
--- a/polkadot/node/subsystem-util/src/rolling_session_window.rs
+++ b/polkadot/node/subsystem-util/src/rolling_session_window.rs
@@ -289,7 +289,7 @@ mod tests {
 	use polkadot_primitives::v1::Header;
 	use sp_core::testing::TaskExecutor;
 
-	const TEST_WINDOW_SIZE: SessionIndex = 6 + 1;
+	const TEST_WINDOW_SIZE: SessionIndex = 6;
 
 	fn dummy_session_info(index: SessionIndex) -> SessionInfo {
 		SessionInfo {