diff --git a/engine.py b/engine.py
index 7fb242e..e44659d 100644
--- a/engine.py
+++ b/engine.py
@@ -544,11 +544,17 @@ class TechnicalEngine:
         tenkan_val = tenkan.iloc[-1]
         kijun_val = kijun.iloc[-1]
 
-        # Current (unshifted) cloud
-        sa = (tenkan.iloc[-1] + kijun.iloc[-1]) / 2
+        # Senkou Spans are plotted 26 bars ahead of their calculation date, so
+        # the cloud boundaries at the *current* bar are the values computed 26
+        # bars ago. Using iloc[-1] would compare price to the future cloud
+        # (look-ahead bias). iloc[-27] gives the correctly lagged cloud.
+        lag = c.ichimoku_kijun  # 26 by default
         sb_raw = (high.rolling(c.ichimoku_senkou_b).max() +
                   low.rolling(c.ichimoku_senkou_b).min()) / 2
-        sb = sb_raw.iloc[-1]
+        if len(sb_raw) < lag + 1:
+            return
+        sa = (tenkan.iloc[-(lag + 1)] + kijun.iloc[-(lag + 1)]) / 2
+        sb = sb_raw.iloc[-(lag + 1)]
 
         if pd.isna(sa) or pd.isna(sb) or pd.isna(tenkan_val) or pd.isna(kijun_val):
             return