diff --git a/crates/fidc-core/src/platform_strategy_spec.rs b/crates/fidc-core/src/platform_strategy_spec.rs
index 71574c9..ddbd8a1 100644
--- a/crates/fidc-core/src/platform_strategy_spec.rs
+++ b/crates/fidc-core/src/platform_strategy_spec.rs
@@ -1999,6 +1999,10 @@ fn instrument_query_id(symbol: &str, board: &str) -> String {
 }
 
 fn normalize_board(symbol: &str, raw_board: Option<&str>) -> String {
+    let has_suffix = symbol.trim().rsplit_once('.').is_some();
+    if has_suffix && symbol_is_kcb(symbol) {
+        return "KSH".to_string();
+    }
     let normalized = raw_board
         .map(str::trim)
         .filter(|value| !value.is_empty())
@@ -2011,7 +2015,7 @@ fn normalize_board(symbol: &str, raw_board: Option<&str>) -> String {
     if let Some((_, suffix)) = symbol.rsplit_once('.') {
         return suffix.to_ascii_uppercase();
     }
-    if symbol.starts_with("688") {
+    if symbol_is_kcb(symbol) {
         return "KSH".to_string();
     }
     if symbol.starts_with('8') || symbol.starts_with('4') {
@@ -2030,10 +2034,29 @@ fn normalize_board(symbol: &str, raw_board: Option<&str>) -> String {
     "UNK".to_string()
 }
 
+fn symbol_is_kcb(symbol: &str) -> bool {
+    let normalized = symbol.trim().to_ascii_uppercase();
+    let Some((code, suffix)) = normalized.rsplit_once('.') else {
+        return normalized.starts_with("688") || normalized.starts_with("689");
+    };
+    suffix == "SH" && (code.starts_with("688") || code.starts_with("689"))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[test]
+    fn normalize_board_classifies_kcb_by_688_689_sh_suffix_only() {
+        assert_eq!(normalize_board("688001.SH", None), "KSH");
+        assert_eq!(normalize_board("689001.SH", None), "KSH");
+        assert_eq!(normalize_board("688001.BJ", None), "BJ");
+        assert_eq!(normalize_board("689001.SZ", None), "SZ");
+        assert_eq!(normalize_board("688001", None), "KSH");
+        assert_eq!(normalize_board("688001", Some("SZ")), "SZ");
+        assert_eq!(normalize_board("688001.SH", Some("SH")), "KSH");
+    }
+
     #[test]
     fn parses_runtime_expression_spec_into_platform_config() {
         let spec = serde_json::json!({