diff --git a/virtualizer/test/resize.test.ts b/virtualizer/test/resize.test.ts
index 0521edb..187ca1f 100644
--- a/virtualizer/test/resize.test.ts
+++ b/virtualizer/test/resize.test.ts
@@ -70,6 +70,21 @@ describe("C.RESIZE — resize", () => {
     expect(v.anchorSubRow).toBe(1);
   });
 
+  it("C.RESIZE.anchor-subrow-clamped-exact — uses exact wrapping for clamp, not estimate", () => {
+    let v = new Virtualizer({ measureWidth: charMeasure, columns: 3, rows: 24 });
+    // "文" is width 2. At columns=3: 1 fits per row (2+2=4 > 3) → 10 exact sub-rows
+    // estimate = ceil(20/3) = 7
+    v.appendLine("文".repeat(10));
+    v.scrollBy(8); // anchorSubRow = 8 (valid in exact range 0-9)
+    expect(v.anchorSubRow).toBe(8);
+
+    // Resize to columns=5: 2 chars fit per row (2+2=4 ≤ 5) → 5 exact sub-rows
+    // estimate = ceil(20/5) = 4
+    // Should clamp to exact(5)-1 = 4, not estimate(4)-1 = 3
+    v.resize(5, 24);
+    expect(v.anchorSubRow).toBe(4);
+  });
+
   it("C.RESIZE.bottom-follow-preserved — isAtBottom survives resize", () => {
     let v = new Virtualizer({ measureWidth: charMeasure, columns: 80, rows: 24 });
     v.appendLine("hello");
diff --git a/virtualizer/test/scroll.test.ts b/virtualizer/test/scroll.test.ts
index 79b8303..82c0ffa 100644
--- a/virtualizer/test/scroll.test.ts
+++ b/virtualizer/test/scroll.test.ts
@@ -115,4 +115,14 @@ describe("C.SCROLL — scrollBy", () => {
       prev = v.currentEstimatedVisualRow;
     }
   });
+
+  it("C.ESTIMATE.current-within-total — holds when exact wraps exceed estimate", () => {
+    let v = new Virtualizer({ measureWidth: charMeasure, columns: 3, rows: 24 });
+    // "文" is width 2. At columns=3: 1 per row → 10 exact sub-rows
+    // estimate = ceil(20/3) = 7
+    v.appendLine("文".repeat(10));
+    v.scrollBy(9); // scroll to last exact sub-row
+    expect(v.currentEstimatedVisualRow).toBeGreaterThanOrEqual(0);
+    expect(v.currentEstimatedVisualRow).toBeLessThan(v.totalEstimatedVisualRows);
+  });
 });
diff --git a/virtualizer/test/wrap-golden.test.ts b/virtualizer/test/wrap-golden.test.ts
index a14af3a..23ece6e 100644
--- a/virtualizer/test/wrap-golden.test.ts
+++ b/virtualizer/test/wrap-golden.test.ts
@@ -81,4 +81,16 @@ describe("G.WRAP — wrapping golden fixtures", () => {
     expect(entry.wrapPoints).toEqual([]);
     expect(entry.totalSubRows).toBe(1);
   });
+
+  it("G.WRAP.wide-char-wider-than-columns — no wrap point at 0", () => {
+    let entry = resolve("文", 1);
+    expect(entry.wrapPoints).toEqual([]);
+    expect(entry.totalSubRows).toBe(1);
+  });
+
+  it("G.WRAP.multiple-wide-chars-at-columns-one — each on own row", () => {
+    let entry = resolve("文字", 1);
+    expect(entry.wrapPoints).toEqual([1]);
+    expect(entry.totalSubRows).toBe(2);
+  });
 });
diff --git a/virtualizer/virtualizer.ts b/virtualizer/virtualizer.ts
index ad9c258..d0be700 100644
--- a/virtualizer/virtualizer.ts
+++ b/virtualizer/virtualizer.ts
@@ -157,19 +157,20 @@ export class Virtualizer {
       }
       this._totalEstimatedVisualRows = newTotal;
 
-      // Clamp anchor sub-row at new width
+      this._columns = columns;
+
+      // Clamp anchor sub-row using exact wrap count at new width
       if (this._ringBuffer.lineCount > 0) {
         let anchorEntry = this._ringBuffer.get(this._anchorLineIndex);
         if (anchorEntry) {
-          let newEstimate = Math.max(1, Math.ceil(anchorEntry.displayWidth / columns));
-          if (this._anchorSubRow >= newEstimate) {
-            this._anchorSubRow = newEstimate - 1;
+          let wrapPoints = this._getWrapPoints(this._anchorLineIndex, anchorEntry.text);
+          let exactSubRows = wrapPoints.length + 1;
+          if (this._anchorSubRow >= exactSubRows) {
+            this._anchorSubRow = exactSubRows - 1;
           }
         }
       }
 
-      this._columns = columns;
-
       // Recompute currentEstimatedVisualRow
       this._recomputeCurrentEstimate();
     }
@@ -318,7 +319,10 @@ export class Virtualizer {
       estimate += this._estimateVisualRows(entry.displayWidth);
     }
     estimate += this._anchorSubRow;
-    this._currentEstimatedVisualRow = estimate;
+    this._currentEstimatedVisualRow = Math.min(
+      estimate,
+      Math.max(this._totalEstimatedVisualRows - 1, 0),
+    );
   }
 
   getLineDisplayWidth(lineIndex: number): number | undefined {
diff --git a/virtualizer/wrap-walker.ts b/virtualizer/wrap-walker.ts
index 0334cf0..79e30ce 100644
--- a/virtualizer/wrap-walker.ts
+++ b/virtualizer/wrap-walker.ts
@@ -53,7 +53,7 @@ export function computeWrapPoints(
     let charLen = cp > 0xffff ? 2 : 1;
     let w = measureWidth(String.fromCodePoint(cp));
 
-    if (w > 0 && col + w > columns) {
+    if (col > 0 && col + w > columns) {
       wrapPoints.push(i);
       col = 0;
     }