diff --git a/config/dedup.us.yaml b/config/dedup.us.yaml
index 69e3acdc3..0b58c06b4 100644
--- a/config/dedup.us.yaml
+++ b/config/dedup.us.yaml
@@ -59,3 +59,33 @@ groups:
     members:
       - { binary: main, vram: 0x80037004, name: func_80037004 }
       - { binary: main, vram: 0x80037334, name: func_80037334 }
+
+  # D1/D2/D3 — Phase-13 CROSS-OVERLAY proof: the byte-identical duplicate pair SC01/005 ≡ SC01/006
+  # (one 0.4.dec, sha1 56760dbe) shares three trivial accessors from ONE source (src/shared/ov_setters.h),
+  # instantiated in place in both overlays' .c. Both `make check BINARY=ov_SC01_005` and `=ov_SC01_006`
+  # stay 56760dbe with the shared C (and with the INCLUDE_ASM stubs) — one match, two binaries. The
+  # generic SETTER/RETCONST macros are reusable fleet-wide (Phase 15 appends members as overlays onboard).
+  - id: D1_ov_dup_8012AD64
+    tier: h_exact
+    hash: 89004be30998a495e3d94dbec7513e3d37f47d8d
+    source: src/shared/ov_setters.h
+    func: SETTER
+    members:
+      - { binary: ov_SC01_005, vram: 0x8012AD64, name: func_8012AD64 }
+      - { binary: ov_SC01_006, vram: 0x8012AD64, name: func_8012AD64 }
+  - id: D2_ov_dup_8012BF4C
+    tier: h_exact
+    hash: b039ed440779107270b60a3b2ca44b3b097b9c87
+    source: src/shared/ov_setters.h
+    func: SETTER
+    members:
+      - { binary: ov_SC01_005, vram: 0x8012BF4C, name: func_8012BF4C }
+      - { binary: ov_SC01_006, vram: 0x8012BF4C, name: func_8012BF4C }
+  - id: D3_ov_dup_8012E27C
+    tier: h_exact
+    hash: 98ab17e54d84a098b4240053ee845921141318c1
+    source: src/shared/ov_setters.h
+    func: RETCONST
+    members:
+      - { binary: ov_SC01_005, vram: 0x8012E27C, name: func_8012E27C }
+      - { binary: ov_SC01_006, vram: 0x8012E27C, name: func_8012E27C }
diff --git a/src/ov_SC01_005/ov_SC01_005.c b/src/ov_SC01_005/ov_SC01_005.c
index 5e0f35d66..d3252e6ac 100644
--- a/src/ov_SC01_005/ov_SC01_005.c
+++ b/src/ov_SC01_005/ov_SC01_005.c
@@ -1,4 +1,5 @@
 #include "common.h"
+#include "../shared/ov_setters.h"   /* dedup share across the SC01/005 ≡ 006 pair (cookbook §11) */
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_80128158);
 
@@ -188,7 +189,7 @@ INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012AD44);
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012AD50);
 
-INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012AD64);
+SETTER(func_8012AD64, 0x34, s16)   /* dedup: shared with ov_SC01_006 (src/shared/ov_setters.h) */
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012AD6C);
 
@@ -264,7 +265,7 @@ INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012BEE8);
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012BF10);
 
-INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012BF4C);
+SETTER(func_8012BF4C, 0x1C, s32)   /* dedup: shared with ov_SC01_006 (src/shared/ov_setters.h) */
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012BF54);
 
@@ -381,7 +382,7 @@ INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012E014);
 
 INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012E138);
 
-INCLUDE_ASM("asm/ov_SC01_005/nonmatchings/ov_SC01_005", func_8012E27C);
+RETCONST(func_8012E27C, 1)   /* dedup: shared with ov_SC01_006 (src/shared/ov_setters.h) */
 
 void func_8012E284(void) {
 }
diff --git a/src/ov_SC01_006/ov_SC01_006.c b/src/ov_SC01_006/ov_SC01_006.c
index 97cead992..eaa38a881 100644
--- a/src/ov_SC01_006/ov_SC01_006.c
+++ b/src/ov_SC01_006/ov_SC01_006.c
@@ -1,4 +1,5 @@
 #include "common.h"
+#include "../shared/ov_setters.h"   /* dedup share across the SC01/005 ≡ 006 pair (cookbook §11) */
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_80128158);
 
@@ -188,7 +189,7 @@ INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012AD44);
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012AD50);
 
-INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012AD64);
+SETTER(func_8012AD64, 0x34, s16)   /* dedup: shared with ov_SC01_005 (src/shared/ov_setters.h) */
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012AD6C);
 
@@ -264,7 +265,7 @@ INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012BEE8);
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012BF10);
 
-INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012BF4C);
+SETTER(func_8012BF4C, 0x1C, s32)   /* dedup: shared with ov_SC01_005 (src/shared/ov_setters.h) */
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012BF54);
 
@@ -381,7 +382,7 @@ INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012E014);
 
 INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012E138);
 
-INCLUDE_ASM("asm/ov_SC01_006/nonmatchings/ov_SC01_006", func_8012E27C);
+RETCONST(func_8012E27C, 1)   /* dedup: shared with ov_SC01_005 (src/shared/ov_setters.h) */
 
 void func_8012E284(void) {
 }
diff --git a/src/shared/ov_setters.h b/src/shared/ov_setters.h
new file mode 100644
index 000000000..348423f7b
--- /dev/null
+++ b/src/shared/ov_setters.h
@@ -0,0 +1,11 @@
+/* src/shared/ov_setters.h — shared parameterized bodies for trivial overlay accessors.
+ * cookbook §11 source-level dedup ("match once, share many"): the body lives ONCE here and is
+ * instantiated IN PLACE (preserving each .c's address order — overlays link functions in source
+ * order) at every member's site. The byte-identical overlay pair SC01/005 ≡ SC01/006 (one
+ * 0.4.dec, sha1 56760dbe) shares these via config/dedup.us.yaml; tools/dedup_integrate.py
+ * byte-gates the share (h_exact). The macros are generic, so the 134-overlay fleet reuses them. */
+#ifndef OV_SETTERS_H
+#define OV_SETTERS_H
+#define SETTER(name, off, ty) void name(void *p, ty v) { *(ty *)((s32)p + (off)) = v; }
+#define RETCONST(name, val)   s32  name(void)          { return (val); }
+#endif