diff --git a/runner/host_session.hpp b/runner/host_session.hpp
index 09760bd..e926daf 100644
--- a/runner/host_session.hpp
+++ b/runner/host_session.hpp
@@ -14,6 +14,7 @@
 #include <map>
 #include <optional>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace retro::runner {
@@ -89,6 +90,9 @@ class HostSession {
         presentation_width_ = width && height ? width : 0;
         presentation_height_ = width && height ? height : 0;
     }
+    std::pair<std::uint32_t,std::uint32_t> presentation_size() const {
+        return {presentation_width_,presentation_height_};
+    }
 
     // After load(): allocate every declared region, filled with its erase
     // value, then from `files[id]` where one is given.
diff --git a/runner/route.cpp b/runner/route.cpp
index aff6c05..168e9f0 100644
--- a/runner/route.cpp
+++ b/runner/route.cpp
@@ -127,6 +127,9 @@ bool Route::open(const std::string& rom, const std::string& package_sha,
             for (const auto& [k,v] : actual) if (!recorded.count(k) || recorded[k] != v) return fail("route identity mismatch: " + k);
             return fail("route identity contains an unsupported key");
         }
+        // Core init/load and anchor restoration may use drawable identity.
+        // The first recorded field can resize, so use the anchor's size.
+        session_.set_presentation_size(boot_.width,boot_.height);
     } else {
         partial_ = args_.record; partial_ += ".partial";
         if (fs::exists(args_.record) || fs::exists(partial_)) return fail("route or partial file already exists");
@@ -144,6 +147,8 @@ bool Route::capture_anchor() {
     if (playback() || !(core_.info->capabilities & RCORE_CAP_SAVESTATE) ||
         !api.serialize_size || !api.serialize || !api.unserialize)
         return fail("this core cannot anchor a replay");
+    const auto [width,height]=session_.presentation_size();
+    boot_.width=width;boot_.height=height;
     const auto size = api.serialize_size();
     if (!size || size > limit/4) return fail("replay anchor is empty or too large");
     anchor_.resize(static_cast<std::size_t>(size));
diff --git a/tests/route_contract_test.cpp b/tests/route_contract_test.cpp
index b8af801..f060d2f 100644
--- a/tests/route_contract_test.cpp
+++ b/tests/route_contract_test.cpp
@@ -5,9 +5,23 @@
 
 using namespace retro::runner;
 namespace {
-void check(bool yes) { if (!yes) { std::cerr << "route contract check failed\n"; std::exit(1); } }
+void check_at(bool yes,int line) { if (!yes) { std::cerr << "route contract check failed at line " << line << '\n'; std::exit(1); } }
+#define check(yes) check_at((yes),__LINE__)
 std::uint64_t digest = 0;
+const rcore_host_api* anchor_host = nullptr;
 std::uint64_t state_hash() { return digest; }
+std::uint64_t anchor_size() { return sizeof digest; }
+rcore_result anchor_write(void* data, std::uint64_t size) {
+    if (!data || size != sizeof digest) return RCORE_ERR_CONTENT;
+    std::memcpy(data,&digest,sizeof digest);return RCORE_OK;
+}
+rcore_result anchor_read(const void* data, std::uint64_t size) {
+    std::uint32_t width=0,height=0;
+    if (!data || size != sizeof digest || !anchor_host ||
+        !anchor_host->presentation_size(anchor_host->host_ctx,&width,&height) ||
+        width != 1440 || height != 900) return RCORE_ERR_CONTENT;
+    std::memcpy(&digest,data,sizeof digest);return RCORE_OK;
+}
 const rcore_option* new_options(std::uint32_t* count) {
     static rcore_option option{};
     option.struct_size=sizeof option;option.key="new_default";option.default_value="off";
@@ -95,5 +109,29 @@ int main(int argc,char** argv) {
     Route compatible(core,reference_session,args,out);check(compatible.open(argv[0],"",".",false));
     args.runner_reference=args.runner;
     Route wrong_reference(core,reference_session,args,out);check(!wrong_reference.open(argv[0],"",".",false));
-    std::cout << "8 seats, 6 axes, clocks, save restoration, state, audio and picture replay pass\n";
+    // The saved anchor's viewport can differ from its first recorded field.
+    // A fresh core must see the saved size before init/load and unserialize.
+    fs::remove(out/"anchor.route");fs::remove(out/"anchor.route.partial");
+    auto anchor_info=info;anchor_info.capabilities|=RCORE_CAP_SAVESTATE;
+    auto anchor_api=api;anchor_api.serialize_size=anchor_size;
+    anchor_api.serialize=anchor_write;anchor_api.unserialize=anchor_read;
+    auto anchor_core=core;anchor_core.info=&anchor_info;anchor_core.api=&anchor_api;
+    TestSink anchor_sink;
+    HostSession anchor_recording(anchor_core,anchor_sink);check(anchor_recording.set_options({},&error));
+    anchor_recording.set_presentation_size(1440,900);
+    RouteArgs anchor_args;anchor_args.runner=fs::absolute(argv[0]);anchor_args.record=out/"anchor.route";
+    Route anchor_recorder(anchor_core,anchor_recording,anchor_args,out);
+    check(anchor_recorder.open(argv[0],"",".",false));anchor_recording.set_route(&anchor_recorder);
+    anchor_host=anchor_recording.host_api();check(anchor_recorder.capture_anchor());
+    drive(anchor_recorder,anchor_recording);
+    HostSession anchor_playing(anchor_core,anchor_sink);check(anchor_playing.set_options({},&error));
+    anchor_sink.noisy=true;
+    anchor_args.play=anchor_args.record;anchor_args.record.clear();
+    Route anchor_player(anchor_core,anchor_playing,anchor_args,out);
+    check(anchor_player.open(argv[0],"",".",false));anchor_playing.set_route(&anchor_player);
+    anchor_host=anchor_playing.host_api();
+    std::uint32_t width=0,height=0;
+    check(anchor_host->presentation_size(anchor_host->host_ctx,&width,&height) && width==1440 && height==900);
+    drive(anchor_player,anchor_playing);
+    std::cout << "8 seats, 6 axes, clocks, save restoration, anchor viewport, state, audio and picture replay pass\n";
 }