diff --git a/include/tanabata.h b/include/tanabata.h
index d2e43cd..8a65144 100644
--- a/include/tanabata.h
+++ b/include/tanabata.h
@@ -59,7 +59,7 @@ int tanabata_sasa_rem_by_path(Tanabata *tanabata, const char *path);
 // ==================== TANZAKU SECTION ==================== //
 
 // Add tanzaku
-int tanabata_tanzaku_add(Tanabata *tanabata, const char *name, const char *alias, const char *description);
+int tanabata_tanzaku_add(Tanabata *tanabata, const char *name, const char *description);
 
 // Remove tanzaku by ID
 int tanabata_tanzaku_rem_by_id(Tanabata *tanabata, uint64_t tanzaku_id);
diff --git a/src/tanabata/sasa.c b/src/tanabata/sasa.c
index 5283142..cbb9f7c 100644
--- a/src/tanabata/sasa.c
+++ b/src/tanabata/sasa.c
@@ -1,13 +1,29 @@
+#include <string.h>
+
 #include "../../include/tanabata.h"
 
 int tanabata_sasa_add(Tanabata *tanabata, const char *path) {
+    for (uint64_t i = 0; i < tanabata->sasahyou.size; i++) {
+        if (tanabata->sasahyou.database[i].id != HOLE_ID && strcmp(tanabata->sasahyou.database[i].path, path) == 0) {
+            fprintf(stderr, "Failed to add sasa: target file is already added\n");
+            return 1;
+        }
+    }
     return sasa_add(&tanabata->sasahyou, path);
 }
 
 int tanabata_sasa_rem_by_id(Tanabata *tanabata, uint64_t sasa_id) {
-    return sasa_rem_by_id(&tanabata->sasahyou, sasa_id);
+    return sasa_rem(&tanabata->sasahyou, sasa_id);
 }
 
 int tanabata_sasa_rem_by_path(Tanabata *tanabata, const char *path) {
-    return sasa_rem_by_path(&tanabata->sasahyou, path);
+    Sasa *current_sasa;
+    for (uint64_t i = 0; i < tanabata->sasahyou.size; i++) {
+        current_sasa = tanabata->sasahyou.database + i;
+        if (current_sasa->id != HOLE_ID && strcmp(current_sasa->path, path) == 0) {
+            return sasa_rem(&tanabata->sasahyou, current_sasa->id);
+        }
+    }
+    fprintf(stderr, "Failed to remove sasa: target sasa does not exist\n");
+    return 1;
 }
diff --git a/src/tanabata/tanzaku.c b/src/tanabata/tanzaku.c
index 0251547..1d97d6b 100644
--- a/src/tanabata/tanzaku.c
+++ b/src/tanabata/tanzaku.c
@@ -1,15 +1,30 @@
+#include <string.h>
 #include "../../include/tanabata.h"
 
-int tanabata_tanzaku_add(Tanabata *tanabata, const char *name, const char *alias, const char *description) {
-    return tanzaku_add(&tanabata->sappyou, name, alias, description);
+int tanabata_tanzaku_add(Tanabata *tanabata, const char *name, const char *description) {
+    for (uint64_t i = 0; i < tanabata->sappyou.size; i++) {
+        if (tanabata->sappyou.database[i].id != HOLE_ID && strcmp(tanabata->sappyou.database[i].name, name) == 0) {
+            fprintf(stderr, "Failed to add tanzaku: target tanzaku is already added\n");
+            return 1;
+        }
+    }
+    return tanzaku_add(&tanabata->sappyou, name, description);
 }
 
 int tanabata_tanzaku_rem_by_id(Tanabata *tanabata, uint64_t tanzaku_id) {
-    return tanzaku_rem_by_id(&tanabata->sappyou, tanzaku_id);
+    return tanzaku_rem(&tanabata->sappyou, tanzaku_id);
 }
 
 int tanabata_tanzaku_rem_by_name(Tanabata *tanabata, const char *name) {
-    return tanzaku_rem_by_name(&tanabata->sappyou, name);
+    Tanzaku *current_tanzaku;
+    for (uint64_t i = 0; i < tanabata->sappyou.size; i++) {
+        current_tanzaku = tanabata->sappyou.database + i;
+        if (current_tanzaku->id != HOLE_ID && strcmp(current_tanzaku->name, name) == 0) {
+            return tanzaku_rem(&tanabata->sappyou, current_tanzaku->id);
+        }
+    }
+    fprintf(stderr, "Failed to remove tanzaku: target tanzaku does not exist\n");
+    return 1;
 }
 
 int tanabata_tanzaku_rem_by_alias(Tanabata *tanabata, const char *alias) {