diff --git a/src/logic/board_value.rs b/src/logic/board_value.rs
index a9d36eb..a45f92f 100644
--- a/src/logic/board_value.rs
+++ b/src/logic/board_value.rs
@@ -1,6 +1,6 @@
 use crate::repr::{Board, Piece, PosMap};
 
-pub struct BoardValueMap(PosMap<i16>);
+pub struct BoardValueMap(PosMap<i8>);
 
 impl BoardValueMap {
     pub fn board_value(&self, board: &Board, color: Piece) -> i16 {
@@ -15,12 +15,13 @@ impl BoardValueMap {
                 // target has position
                 value
             })
+            .map(|x| x as i16)
             .sum()
     }
 
     /// Weights from: https://repub.eur.nl/pub/7142/ei2005-47.pdf
     pub const fn weighted() -> Self {
-        const POSITION_VALUES: [[i16; 8]; 8] = [
+        const POSITION_VALUES: [[i8; 8]; 8] = [
             [100, -20, 10, 5, 5, 10, -20, 100],
             [-20, -50, -2, -2, -2, -2, -50, -20],
             [10, -2, -1, -1, -1, -1, -2, 10],