diff --git a/strafe-client/src/session.rs b/strafe-client/src/session.rs
index 71ea9ca..8ddaca7 100644
--- a/strafe-client/src/session.rs
+++ b/strafe-client/src/session.rs
@@ -1,6 +1,6 @@
 // session represents the non-hardware state of the client.
 // Ideally it is a deterministic state which is atomically updated by instructions, same as the simulation state.
-use strafesnet_common::physics::Time as PhysicsTime;
+use strafesnet_common::physics::{Instruction as PhysicsInputInstruction,Time as PhysicsTime};
 use strafesnet_common::timer::{Scaled,Timer};
 use strafesnet_common::physics::TimeInner as PhysicsTimeInner;
 use strafesnet_common::session::TimeInner as SessionTimeInner;
@@ -16,9 +16,15 @@ pub struct Simulation{
 	physics:crate::physics::PhysicsContext,
 }
 
+pub struct Replay{
+	instruction:Vec<PhysicsInputInstruction>,
+	simulation:Simulation,
+}
+
 pub struct SessionState{
 	user_settings:crate::settings::UserSettings,
 	mouse_interpolator:crate::mouse_interpolator::MouseInterpolator,
 	//gui:GuiState
 	simulation:Simulation,
+	replays:Vec<Replay>,
 }