diff --git a/AGENTS.md b/AGENTS.md
index 5381cbd8f..a528fc4a0 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -18,6 +18,7 @@ This document compiles the Open Chinese Convert (OpenCC) project information to
 - Reserve `TWVariantsPhrases.txt` for phrase-level exceptions to Taiwan variant character conversion, especially when a phrase must override character-level mappings from `TWVariants.txt`. It is part of `s2tw`, `s2twp`, and `t2tw`; using it for vocabulary translations will incorrectly affect `s2tw`.
 - For `s2twp`, remember the conversion chain is `STPhrases/STCharacters -> TWPhrases -> TWVariantsPhrases/TWVariants`. If a Simplified input phrase must be matched later by `TWPhrases`, add a necessary Simplified-to-Traditional segmentation entry to `STPhrases.txt`; otherwise the phrase can be split before the Taiwan vocabulary stage.
 - Keep `TWPhrases.txt` and `TWPhrasesRev.txt` bidirectionally consistent. Run `bazel test //data/dictionary:dictionary_TWPhrases_reverse_mapping_test` after editing either file.
+- For intentional one-way Taiwan vocabulary conversions, keep the forward mapping in `TWPhrases.txt` and add a self-mapping candidate on both sides so `tw2sp` can preserve the Taiwan term. For example, to make `s2twp` convert `信道 -> 通道` without forcing `tw2sp` to convert every `通道` back to `信道`, use `信道 -> 通道` plus `通道 -> 通道` in `TWPhrases.txt`, and make `TWPhrasesRev.txt` map `通道 -> 通道 信道`. The self-mapping keeps the reverse dictionary structurally consistent while making the reverse conversion prefer unchanged `通道`.
 - Use `python3 data/scripts/sort.py <file> <file>` for edited dictionary files instead of hand-sorting. Dictionary tests enforce sorted unique keys.
 - Add tests to `test/testcases/testcases.json` against the config that actually uses the dictionary. Taiwan vocabulary in `TWPhrases.txt` should normally be tested with `s2twp` / `tw2sp`, not `s2tw`.
 
diff --git a/data/dictionary/TWPhrases.txt b/data/dictionary/TWPhrases.txt
index 5d04c7df6..7d63eebb7 100644
--- a/data/dictionary/TWPhrases.txt
+++ b/data/dictionary/TWPhrases.txt
@@ -596,6 +596,7 @@ U盤	隨身碟
 轉義字符	跳脫字元
 通信	通訊
 通訊卡	通話卡
+通道	通道
 通配符	萬用字元
 連接	連線
 連接器	聯結器
diff --git a/data/dictionary/TWPhrasesRev.txt b/data/dictionary/TWPhrasesRev.txt
index 4fb9685d2..d2f5a5e1e 100644
--- a/data/dictionary/TWPhrasesRev.txt
+++ b/data/dictionary/TWPhrasesRev.txt
@@ -594,7 +594,7 @@ SQL隱碼攻擊	SQL注入 SQL注入攻擊
 通訊	通信
 通話卡	通訊卡
 通話記錄	聯繫歷史
-通道	信道
+通道	通道 信道
 速食麵	方便麪
 連結	鏈接
 連結串列	鏈表
diff --git a/test/testcases/testcases.json b/test/testcases/testcases.json
index b0378fec1..c5d60fc8b 100755
--- a/test/testcases/testcases.json
+++ b/test/testcases/testcases.json
@@ -379,6 +379,20 @@
         "t2s": "写一个解算器程式来解决方程式"
       }
     },
+    {
+      "id": "BYVoid_OpenCC_PR_1291_s2twp",
+      "input": "现代无线通信技术可以通过无线信道进行高速传输，不受电缆束缚",
+      "expected": {
+        "s2twp": "現代無線通訊技術可以通過無線通道進行高速傳輸，不受電纜束縛"
+      }
+    },
+    {
+      "id": "BYVoid_OpenCC_PR_1291_tw2sp",
+      "input": "現代無線通訊技術可以透過無線通道進行高速傳輸，不受電纜束縛",
+      "expected": {
+        "tw2sp": "现代无线通信技术可以透过无线通道进行高速传输，不受电缆束缚"
+      }
+    },
     {
       "id": "ByVoid_OpenCC_Issue950_AlgorithmConversion",
       "input": "算法",