diff --git a/apps/web/src/reader/CbzReader.tsx b/apps/web/src/reader/CbzReader.tsx
index d75c56c..7e82fc3 100644
--- a/apps/web/src/reader/CbzReader.tsx
+++ b/apps/web/src/reader/CbzReader.tsx
@@ -10,6 +10,7 @@ type PageCommitStrategy = "immediate" | "queued";
 const VERTICAL_ANCHOR_TOLERANCE_PX = 24;
 const VERTICAL_ANCHOR_STABLE_FRAMES = 18;
 const VERTICAL_ANCHOR_MAX_ATTEMPTS = 180;
+const VERTICAL_INITIAL_SYNC_MAX_ATTEMPTS = 180;
 
 export function CbzReader({
   bookId,
@@ -33,6 +34,9 @@ export function CbzReader({
   const verticalUserScrollRef = useRef(false);
   const verticalAnchorTargetPageRef = useRef<number | null>(null);
   const verticalAnchorFrameRef = useRef<number | null>(null);
+  const verticalInitialSyncFrameRef = useRef<number | null>(null);
+  const verticalInitialSyncAttemptRef = useRef(0);
+  const verticalInitialSyncDoneRef = useRef(false);
   const verticalAnchorAttemptRef = useRef(0);
   const verticalAnchorStableFramesRef = useRef(0);
   const [pages, setPages] = useState<CbzPagesDto | null>(null);
@@ -83,10 +87,15 @@ export function CbzReader({
     if (verticalAnchorFrameRef.current !== null) cancelAnimationFrame(verticalAnchorFrameRef.current);
     verticalAnchorFrameRef.current = null;
   }, []);
+  const clearVerticalInitialSync = useCallback(() => {
+    if (verticalInitialSyncFrameRef.current !== null) cancelAnimationFrame(verticalInitialSyncFrameRef.current);
+    verticalInitialSyncFrameRef.current = null;
+  }, []);
   const commitVisiblePage = useCallback(
     (stage: HTMLElement, allowInitialCommit = false) => {
       if (!pages || !verticalTrackingReadyRef.current) return;
       if (!allowInitialCommit && !verticalUserScrollRef.current) return;
+      if (allowInitialCommit && verticalInitialSyncDoneRef.current) return;
       const stageRect = stage.getBoundingClientRect();
       const visiblePage = majorityVisiblePage(
         Array.from(stage.querySelectorAll<HTMLElement>("[data-reader-page]")).map((element) => {
@@ -96,10 +105,34 @@ export function CbzReader({
         stageRect.top,
         stageRect.bottom
       );
-      if (visiblePage && visiblePage !== currentPage) onPageCommit(clampReaderPage(visiblePage, pages.pageCount), pages.pageCount, 1, "queued");
+      if (visiblePage && visiblePage !== currentPage) {
+        if (allowInitialCommit) verticalInitialSyncDoneRef.current = true;
+        onPageCommit(clampReaderPage(visiblePage, pages.pageCount), pages.pageCount, 1, "queued");
+      }
     },
     [currentPage, onPageCommit, pages]
   );
+  const scheduleInitialVisibleSync = useCallback(
+    (stage: HTMLElement) => {
+      clearVerticalInitialSync();
+      if (!(stage.scrollHeight > stage.clientHeight)) return;
+      verticalInitialSyncAttemptRef.current = 0;
+
+      const sync = () => {
+        verticalInitialSyncFrameRef.current = null;
+        if (verticalUserScrollRef.current || verticalInitialSyncDoneRef.current) return;
+        if (verticalTrackingReadyRef.current && stage.scrollTop > Math.max(32, stage.clientHeight * 0.5)) {
+          commitVisiblePage(stage, true);
+        }
+        verticalInitialSyncAttemptRef.current += 1;
+        if (verticalInitialSyncAttemptRef.current >= VERTICAL_INITIAL_SYNC_MAX_ATTEMPTS) return;
+        verticalInitialSyncFrameRef.current = requestAnimationFrame(sync);
+      };
+
+      verticalInitialSyncFrameRef.current = requestAnimationFrame(sync);
+    },
+    [clearVerticalInitialSync, commitVisiblePage]
+  );
   const stabilizeVerticalAnchor = useCallback(
     (targetPage: number) => {
       clearVerticalAnchorFrame();
@@ -125,6 +158,7 @@ export function CbzReader({
           if (verticalAnchorStableFramesRef.current >= VERTICAL_ANCHOR_STABLE_FRAMES) {
             verticalTrackingReadyRef.current = true;
             commitVisiblePage(stage, true);
+            scheduleInitialVisibleSync(stage);
             return;
           }
           verticalAnchorAttemptRef.current += 1;
@@ -135,7 +169,7 @@ export function CbzReader({
 
       verticalAnchorFrameRef.current = requestAnimationFrame(measure);
     },
-    [clearVerticalAnchorFrame, commitVisiblePage]
+    [clearVerticalAnchorFrame, commitVisiblePage, scheduleInitialVisibleSync]
   );
 
   const go = useCallback(
@@ -198,14 +232,19 @@ export function CbzReader({
       verticalTrackingReadyRef.current = false;
       verticalUserScrollRef.current = false;
       verticalAnchorTargetPageRef.current = null;
+      verticalInitialSyncDoneRef.current = false;
       clearVerticalAnchorFrame();
+      clearVerticalInitialSync();
       return;
     }
-    if (previousModeRef.current !== "vertical" || (!verticalUserScrollRef.current && verticalAnchorTargetPageRef.current !== currentPage)) {
+    const enteringVertical = previousModeRef.current !== "vertical";
+    if (enteringVertical || (!verticalUserScrollRef.current && verticalAnchorTargetPageRef.current !== currentPage)) {
       pendingVerticalAnchorRef.current = true;
       verticalTrackingReadyRef.current = false;
       verticalUserScrollRef.current = false;
+      if (enteringVertical) verticalInitialSyncDoneRef.current = false;
       clearVerticalAnchorFrame();
+      clearVerticalInitialSync();
     }
     if (pendingVerticalAnchorRef.current) {
       const target = frameRef.current?.querySelector<HTMLElement>(`[data-reader-page="${currentPage}"]`);
@@ -218,7 +257,7 @@ export function CbzReader({
       stabilizeVerticalAnchor(currentPage);
     }
     previousModeRef.current = mode;
-  }, [clearVerticalAnchorFrame, currentPage, mode, pages, stabilizeVerticalAnchor]);
+  }, [clearVerticalAnchorFrame, clearVerticalInitialSync, currentPage, mode, pages, stabilizeVerticalAnchor]);
 
   useEffect(() => {
     if (mode !== "vertical" || !pages) return;
@@ -245,6 +284,7 @@ export function CbzReader({
     stage.addEventListener("pointerdown", markUserScroll, { passive: true });
     keyTarget?.addEventListener("keydown", markUserScrollKey);
     stage.addEventListener("scroll", onScroll, { passive: true });
+    scheduleInitialVisibleSync(stage);
     updateVisiblePage();
     return () => {
       if (frameId) cancelAnimationFrame(frameId);
@@ -254,9 +294,10 @@ export function CbzReader({
       keyTarget?.removeEventListener("keydown", markUserScrollKey);
       stage.removeEventListener("scroll", onScroll);
     };
-  }, [commitVisiblePage, mode, pages]);
+  }, [commitVisiblePage, mode, pages, scheduleInitialVisibleSync]);
 
   useEffect(() => () => clearVerticalAnchorFrame(), [clearVerticalAnchorFrame]);
+  useEffect(() => () => clearVerticalInitialSync(), [clearVerticalInitialSync]);
 
   if (documentError) {
     return (
diff --git a/apps/web/src/reader/PdfReader.tsx b/apps/web/src/reader/PdfReader.tsx
index 1afcc9f..d4b53ec 100644
--- a/apps/web/src/reader/PdfReader.tsx
+++ b/apps/web/src/reader/PdfReader.tsx
@@ -32,6 +32,7 @@ type PdfPageStatus = "idle" | "loading" | PdfRenderResult | "render-failed";
 const VERTICAL_ANCHOR_TOLERANCE_PX = 24;
 const VERTICAL_ANCHOR_STABLE_FRAMES = 18;
 const VERTICAL_ANCHOR_MAX_ATTEMPTS = 180;
+const VERTICAL_INITIAL_SYNC_MAX_ATTEMPTS = 180;
 
 function pdfTechnicalMessage(error: unknown) {
   if (error instanceof Error && error.message.trim()) return `${error.name}: ${error.message}`;
@@ -159,6 +160,9 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
   const verticalUserScrollRef = useRef(false);
   const verticalAnchorTargetPageRef = useRef<number | null>(null);
   const verticalAnchorFrameRef = useRef<number | null>(null);
+  const verticalInitialSyncFrameRef = useRef<number | null>(null);
+  const verticalInitialSyncAttemptRef = useRef(0);
+  const verticalInitialSyncDoneRef = useRef(false);
   const verticalAnchorAttemptRef = useRef(0);
   const verticalAnchorStableFramesRef = useRef(0);
   const [documentProxy, setDocumentProxy] = useState<pdfjs.PDFDocumentProxy | null>(null);
@@ -179,10 +183,15 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
     if (verticalAnchorFrameRef.current !== null) cancelAnimationFrame(verticalAnchorFrameRef.current);
     verticalAnchorFrameRef.current = null;
   }, []);
+  const clearVerticalInitialSync = useCallback(() => {
+    if (verticalInitialSyncFrameRef.current !== null) cancelAnimationFrame(verticalInitialSyncFrameRef.current);
+    verticalInitialSyncFrameRef.current = null;
+  }, []);
   const commitVisiblePage = useCallback(
     (stage: HTMLElement, allowInitialCommit = false) => {
       if (!verticalTrackingReadyRef.current) return;
       if (!allowInitialCommit && !verticalUserScrollRef.current) return;
+      if (allowInitialCommit && verticalInitialSyncDoneRef.current) return;
       const stageRect = stage.getBoundingClientRect();
       const visiblePage = majorityVisiblePage(
         Array.from(stage.querySelectorAll<HTMLElement>("[data-reader-page]")).map((element) => {
@@ -192,10 +201,34 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
         stageRect.top,
         stageRect.bottom
       );
-      if (visiblePage && visiblePage !== currentPage) onPageCommit(clampReaderPage(visiblePage, pages), pages, 1, "queued");
+      if (visiblePage && visiblePage !== currentPage) {
+        if (allowInitialCommit) verticalInitialSyncDoneRef.current = true;
+        onPageCommit(clampReaderPage(visiblePage, pages), pages, 1, "queued");
+      }
     },
     [currentPage, onPageCommit, pages]
   );
+  const scheduleInitialVisibleSync = useCallback(
+    (stage: HTMLElement) => {
+      clearVerticalInitialSync();
+      if (!(stage.scrollHeight > stage.clientHeight)) return;
+      verticalInitialSyncAttemptRef.current = 0;
+
+      const sync = () => {
+        verticalInitialSyncFrameRef.current = null;
+        if (verticalUserScrollRef.current || verticalInitialSyncDoneRef.current) return;
+        if (verticalTrackingReadyRef.current && stage.scrollTop > Math.max(32, stage.clientHeight * 0.5)) {
+          commitVisiblePage(stage, true);
+        }
+        verticalInitialSyncAttemptRef.current += 1;
+        if (verticalInitialSyncAttemptRef.current >= VERTICAL_INITIAL_SYNC_MAX_ATTEMPTS) return;
+        verticalInitialSyncFrameRef.current = requestAnimationFrame(sync);
+      };
+
+      verticalInitialSyncFrameRef.current = requestAnimationFrame(sync);
+    },
+    [clearVerticalInitialSync, commitVisiblePage]
+  );
   const stabilizeVerticalAnchor = useCallback(
     (targetPage: number) => {
       clearVerticalAnchorFrame();
@@ -221,6 +254,7 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
           if (verticalAnchorStableFramesRef.current >= VERTICAL_ANCHOR_STABLE_FRAMES) {
             verticalTrackingReadyRef.current = true;
             commitVisiblePage(stage, true);
+            scheduleInitialVisibleSync(stage);
             return;
           }
           verticalAnchorAttemptRef.current += 1;
@@ -231,7 +265,7 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
 
       verticalAnchorFrameRef.current = requestAnimationFrame(measure);
     },
-    [clearVerticalAnchorFrame, commitVisiblePage]
+    [clearVerticalAnchorFrame, commitVisiblePage, scheduleInitialVisibleSync]
   );
 
   const go = useCallback(
@@ -264,14 +298,19 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
       verticalTrackingReadyRef.current = false;
       verticalUserScrollRef.current = false;
       verticalAnchorTargetPageRef.current = null;
+      verticalInitialSyncDoneRef.current = false;
       clearVerticalAnchorFrame();
+      clearVerticalInitialSync();
       return;
     }
-    if (previousModeRef.current !== "vertical" || (!verticalUserScrollRef.current && verticalAnchorTargetPageRef.current !== currentPage)) {
+    const enteringVertical = previousModeRef.current !== "vertical";
+    if (enteringVertical || (!verticalUserScrollRef.current && verticalAnchorTargetPageRef.current !== currentPage)) {
       pendingVerticalAnchorRef.current = true;
       verticalTrackingReadyRef.current = false;
       verticalUserScrollRef.current = false;
+      if (enteringVertical) verticalInitialSyncDoneRef.current = false;
       clearVerticalAnchorFrame();
+      clearVerticalInitialSync();
     }
     if (pendingVerticalAnchorRef.current) {
       const target = frameRef.current?.querySelector<HTMLElement>(`[data-reader-page="${currentPage}"]`);
@@ -284,7 +323,7 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
       stabilizeVerticalAnchor(currentPage);
     }
     previousModeRef.current = mode;
-  }, [clearVerticalAnchorFrame, currentPage, documentProxy, mode, stabilizeVerticalAnchor]);
+  }, [clearVerticalAnchorFrame, clearVerticalInitialSync, currentPage, documentProxy, mode, stabilizeVerticalAnchor]);
 
   useEffect(() => {
     if (mode !== "vertical") return;
@@ -311,6 +350,7 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
     stage.addEventListener("pointerdown", markUserScroll, { passive: true });
     keyTarget?.addEventListener("keydown", markUserScrollKey);
     stage.addEventListener("scroll", onScroll, { passive: true });
+    scheduleInitialVisibleSync(stage);
     updateVisiblePage();
     return () => {
       if (frameId) cancelAnimationFrame(frameId);
@@ -320,9 +360,10 @@ export function PdfReader({ url, page, backHref, zoom, mode, onPageCommit, onCon
       keyTarget?.removeEventListener("keydown", markUserScrollKey);
       stage.removeEventListener("scroll", onScroll);
     };
-  }, [commitVisiblePage, mode, pages]);
+  }, [commitVisiblePage, mode, pages, scheduleInitialVisibleSync]);
 
   useEffect(() => () => clearVerticalAnchorFrame(), [clearVerticalAnchorFrame]);
+  useEffect(() => () => clearVerticalInitialSync(), [clearVerticalInitialSync]);
 
   useEffect(() => {
     const frame = frameRef.current;