diff --git a/crates/loro-core/src/container/map/map_container.rs b/crates/loro-core/src/container/map/map_container.rs
index f1ee61d1..78976ee7 100644
--- a/crates/loro-core/src/container/map/map_container.rs
+++ b/crates/loro-core/src/container/map/map_container.rs
@@ -6,7 +6,7 @@ use crate::{
     log_store::LogStoreWeakRef,
     op::{InsertContent, Op, RichOp},
     op::{OpContent, RemoteOp},
-    span::{HasId, IdSpan},
+    span::IdSpan,
     value::{InsertValue, LoroValue},
     version::TotalOrderStamp,
     InternalString, LogStore,
@@ -57,7 +57,7 @@ impl MapContainer {
         let counter = id.counter;
         let container = store.get_container_idx(self_id).unwrap();
         store.append_local_ops(&[Op {
-            id,
+            counter: id.counter,
             container,
             content: OpContent::Normal {
                 content: InsertContent::Dyn(Box::new(MapSet {
@@ -109,7 +109,7 @@ impl Container for MapContainer {
                     let v: &MapSet = content.as_map().unwrap();
                     let order = TotalOrderStamp {
                         lamport,
-                        client_id: op.id_start().client_id,
+                        client_id: id_span.client_id,
                     };
                     if let Some(slot) = self.state.get_mut(&v.key) {
                         if slot.order < order {
@@ -123,7 +123,7 @@ impl Container for MapContainer {
                             ValueSlot {
                                 value: v.value.clone(),
                                 order,
-                                counter: op.id_start().counter,
+                                counter: op.counter,
                             },
                         );
 
diff --git a/crates/loro-core/src/container/text/text_container.rs b/crates/loro-core/src/container/text/text_container.rs
index fcf1c016..2a1a6dde 100644
--- a/crates/loro-core/src/container/text/text_container.rs
+++ b/crates/loro-core/src/container/text/text_container.rs
@@ -1,6 +1,6 @@
 use std::ops::Range;
 
-use rle::{rle_tree::tree_trait::CumulateTreeTrait, RleTree, Sliceable};
+use rle::{rle_tree::tree_trait::CumulateTreeTrait, HasLength, RleTree, Sliceable};
 use smallvec::{smallvec, SmallVec};
 
 use crate::{
@@ -11,7 +11,7 @@ use crate::{
     log_store::LogStoreWeakRef,
     op::{InsertContent, Op, OpContent, RemoteOp},
     smstring::SmString,
-    span::{HasIdSpan, IdSpan},
+    span::{HasCounter, HasCounterSpan, HasIdSpan, IdSpan},
     value::LoroValue,
     LogStore, VersionVector,
 };
@@ -82,7 +82,10 @@ impl TextContainer {
             },
             store.get_or_create_container_idx(&self.id),
         );
-        let last_id = op.id_last();
+        let last_id = ID::new(
+            store.this_client_id,
+            op.counter + op.atom_len() as Counter - 1,
+        );
         store.append_local_ops(&[op]);
         self.head = smallvec![last_id];
         self.vv.set_last(last_id);
@@ -106,7 +109,7 @@ impl TextContainer {
             store.get_or_create_container_idx(&self.id),
         );
 
-        let last_id = op.id_last();
+        let last_id = ID::new(store.this_client_id, op.ctr_last());
         store.append_local_ops(&[op]);
         self.state.delete_range(Some(pos), Some(pos + len));
         self.head = smallvec![last_id];
@@ -198,7 +201,13 @@ impl Container for TextContainer {
             for op in change.ops.iter() {
                 if op.container == self_idx {
                     // TODO: convert op to local
-                    self.tracker.apply(op.id, &op.content)
+                    self.tracker.apply(
+                        ID {
+                            client_id: change.id.client_id,
+                            counter: op.counter,
+                        },
+                        &op.content,
+                    )
                 }
             }
         }
diff --git a/crates/loro-core/src/log_store.rs b/crates/loro-core/src/log_store.rs
index 42b8de81..90018c31 100644
--- a/crates/loro-core/src/log_store.rs
+++ b/crates/loro-core/src/log_store.rs
@@ -19,7 +19,7 @@ use crate::{
     id::{ClientID, Counter},
     isomorph::{Irc, IsoRw, IsoWeak},
     op::RemoteOp,
-    span::{HasIdSpan, HasLamportSpan, IdSpan},
+    span::{HasCounterSpan, HasIdSpan, HasLamportSpan, IdSpan},
     Lamport, Op, Timestamp, VersionVector, ID,
 };
 
@@ -257,7 +257,9 @@ impl LogStore {
             client_id: self.this_client_id,
             counter: self.get_next_counter(self.this_client_id),
         };
-        let last_id = ops.last().unwrap().id_last();
+        let last = ops.last().unwrap();
+        let last_ctr = last.ctr_last();
+        let last_id = ID::new(self.this_client_id, last_ctr);
         let change = Change {
             id,
             deps: std::mem::replace(&mut self.frontier, smallvec::smallvec![last_id]),
diff --git a/crates/loro-core/src/log_store/iter.rs b/crates/loro-core/src/log_store/iter.rs
index 155bb5e4..579514ea 100644
--- a/crates/loro-core/src/log_store/iter.rs
+++ b/crates/loro-core/src/log_store/iter.rs
@@ -1,7 +1,6 @@
 use crate::Op;
 
 use crate::change::Lamport;
-use crate::container::ContainerID;
 
 use crate::id::ClientID;
 use crate::id::ContainerIdx;
@@ -93,7 +92,7 @@ impl<'a> Iterator for OpSpanIter<'a> {
 
                 return Some(RichOp {
                     op,
-                    lamport: (op.id.counter - change.id.counter) as Lamport + change.lamport,
+                    lamport: (op.counter - change.id.counter) as Lamport + change.lamport,
                     timestamp: change.timestamp,
                 });
             } else {
diff --git a/crates/loro-core/src/op.rs b/crates/loro-core/src/op.rs
index eba6a63b..508ec170 100644
--- a/crates/loro-core/src/op.rs
+++ b/crates/loro-core/src/op.rs
@@ -2,7 +2,7 @@ use crate::{
     change::{Lamport, Timestamp},
     container::ContainerID,
     id::{Counter, ID},
-    span::HasId,
+    span::HasCounter,
     LogStore,
 };
 use rle::{HasIndex, HasLength, Mergable, Sliceable};
@@ -31,14 +31,14 @@ pub enum OpType {
 /// A Op may have multiple atomic operations, since Op can be merged.
 #[derive(Debug, Clone)]
 pub struct Op {
-    pub(crate) id: ID,
+    pub(crate) counter: Counter,
     pub(crate) container: u32,
     pub(crate) content: OpContent,
 }
 
 #[derive(Debug, Clone)]
 pub struct RemoteOp {
-    pub(crate) id: ID,
+    pub(crate) counter: Counter,
     pub(crate) container: ContainerID,
     pub(crate) content: OpContent,
 }
@@ -47,7 +47,7 @@ impl Op {
     #[inline]
     pub(crate) fn new(id: ID, content: OpContent, container: u32) -> Self {
         Op {
-            id,
+            counter: id.counter,
             content,
             container,
         }
@@ -69,7 +69,7 @@ impl Op {
     pub(crate) fn convert(self, log: &LogStore) -> RemoteOp {
         let container = log.get_container_id(self.container).clone();
         RemoteOp {
-            id: self.id,
+            counter: self.counter,
             container,
             content: self.content,
         }
@@ -78,11 +78,10 @@ impl Op {
 
 impl RemoteOp {
     pub(crate) fn convert(self, log: &mut LogStore) -> Op {
-        let id = self.id;
         let container = log.get_or_create_container_idx(&self.container);
         let content = self.content;
         Op {
-            id,
+            counter: self.counter,
             container,
             content,
         }
@@ -91,7 +90,7 @@ impl RemoteOp {
 
 impl Mergable for Op {
     fn is_mergable(&self, other: &Self, cfg: &()) -> bool {
-        self.id.is_connected_id(&other.id, self.content_len())
+        self.counter + self.content_len() as Counter == other.counter
             && self.content.is_mergable(&other.content, cfg)
             && self.container == other.container
     }
@@ -135,10 +134,7 @@ impl Sliceable for Op {
         assert!(to > from);
         let content: OpContent = self.content.slice(from, to);
         Op {
-            id: ID {
-                client_id: self.id.client_id,
-                counter: (self.id.counter + from as Counter),
-            },
+            counter: (self.counter + from as Counter),
             content,
             container: self.container.clone(),
         }
@@ -147,7 +143,7 @@ impl Sliceable for Op {
 
 impl Mergable for RemoteOp {
     fn is_mergable(&self, other: &Self, cfg: &()) -> bool {
-        self.id.is_connected_id(&other.id, self.content_len())
+        self.counter + self.content_len() as Counter == other.counter
             && self.content.is_mergable(&other.content, cfg)
             && self.container == other.container
     }
@@ -191,22 +187,13 @@ impl Sliceable for RemoteOp {
         assert!(to > from);
         let content: OpContent = self.content.slice(from, to);
         RemoteOp {
-            id: ID {
-                client_id: self.id.client_id,
-                counter: (self.id.counter + from as Counter),
-            },
+            counter: (self.counter + from as Counter),
             content,
             container: self.container.clone(),
         }
     }
 }
 
-impl HasId for Op {
-    fn id_start(&self) -> ID {
-        self.id
-    }
-}
-
 pub struct RichOp<'a> {
     pub op: &'a Op,
     pub lamport: Lamport,
@@ -217,7 +204,7 @@ impl HasIndex for Op {
     type Int = Counter;
 
     fn get_start_index(&self) -> Self::Int {
-        self.id.counter
+        self.counter
     }
 }
 
@@ -225,6 +212,18 @@ impl HasIndex for RemoteOp {
     type Int = Counter;
 
     fn get_start_index(&self) -> Self::Int {
-        self.id.counter
+        self.counter
+    }
+}
+
+impl HasCounter for Op {
+    fn ctr_start(&self) -> Counter {
+        self.counter
+    }
+}
+
+impl HasCounter for RemoteOp {
+    fn ctr_start(&self) -> Counter {
+        self.counter
     }
 }
diff --git a/crates/loro-core/src/span.rs b/crates/loro-core/src/span.rs
index 8a8c4466..e7d3c06e 100644
--- a/crates/loro-core/src/span.rs
+++ b/crates/loro-core/src/span.rs
@@ -218,6 +218,36 @@ pub trait HasId {
     fn id_start(&self) -> ID;
 }
 
+pub trait HasCounter {
+    fn ctr_start(&self) -> Counter;
+}
+
+pub trait HasCounterSpan: HasCounter + HasLength {
+    fn ctr_end(&self) -> Counter {
+        self.ctr_start() + self.atom_len() as Counter
+    }
+
+    fn ctr_last(&self) -> Counter {
+        self.ctr_start() + self.atom_len() as Counter - 1
+    }
+
+    fn ctr_span(&self) -> CounterSpan {
+        CounterSpan {
+            start: self.ctr_start(),
+            end: self.ctr_end(),
+        }
+    }
+}
+
+impl<T: HasCounter + HasLength> HasCounterSpan for T {}
+
+impl<T: HasId> HasCounter for T {
+    #[inline]
+    fn ctr_start(&self) -> Counter {
+        self.id_start().counter
+    }
+}
+
 pub trait HasIdSpan: HasId + HasLength {
     fn intersect<T: HasIdSpan>(&self, other: &T) -> bool {
         let self_start = self.id_start();
@@ -250,14 +280,6 @@ pub trait HasIdSpan: HasId + HasLength {
         self.id_start().inc(self.content_len() as i32 - 1)
     }
 
-    fn ctr_last(&self) -> Counter {
-        self.id_start().counter + self.content_len() as i32 - 1
-    }
-
-    fn ctr_first(&self) -> Counter {
-        self.id_start().counter
-    }
-
     fn contains_id(&self, id: ID) -> bool {
         let id_start = self.id_start();
         if id.client_id != id_start.client_id {