diff --git a/core/hakmem_shared_pool.c b/core/hakmem_shared_pool.c
index 89ac6c16..c193f640 100644
--- a/core/hakmem_shared_pool.c
+++ b/core/hakmem_shared_pool.c
@@ -523,6 +523,28 @@ static SharedSSMeta* sp_meta_find_or_create(SuperSlab* ss) {
 // Phase 12-1.x: Acquire Helper Boxes (Stage 0.5/1/2/3)
 // ============================================================================
 
+// Debug / stats helper (Stage hits)
+static inline void sp_stage_stats_dump_if_enabled(void) {
+#if !HAKMEM_BUILD_RELEASE
+    static int dump_en = -1;
+    if (__builtin_expect(dump_en == -1, 0)) {
+        const char* e = getenv("HAKMEM_SHARED_POOL_STAGE_STATS");
+        dump_en = (e && *e && *e != '0') ? 1 : 0;
+    }
+    if (!dump_en) return;
+
+    // 代表として class0 のカウンタを出す（全クラス合計が欲しければ別途集計）
+    fprintf(stderr,
+            "[SP_STAGE_STATS] c0: stage0.5=%u stage1=%u stage2=%u stage3=%u\n",
+            (unsigned)atomic_load_explicit(&g_sp_stage0_hits[0], memory_order_relaxed),
+            (unsigned)atomic_load_explicit(&g_sp_stage1_hits[0], memory_order_relaxed),
+            (unsigned)atomic_load_explicit(&g_sp_stage2_hits[0], memory_order_relaxed),
+            (unsigned)atomic_load_explicit(&g_sp_stage3_hits[0], memory_order_relaxed));
+#else
+    (void)g_sp_stage0_hits; (void)g_sp_stage1_hits; (void)g_sp_stage2_hits; (void)g_sp_stage3_hits;
+#endif
+}
+
 // Stage 0.5: EMPTY slab direct scan（registry ベースの EMPTY 再利用）
 static inline int
 sp_acquire_from_empty_scan(int class_idx, SuperSlab** ss_out, int* slab_idx_out, int dbg_acquire)