diff --git a/board/src/bitboard/bitboard.rs b/board/src/bitboard/bitboard.rs
index 132f329..991c70f 100644
--- a/board/src/bitboard/bitboard.rs
+++ b/board/src/bitboard/bitboard.rs
@@ -1,5 +1,6 @@
 // Eryn Wells <eryn@erynwells.me>
 
+use super::library::{FILES, RANKS};
 use super::BitScanner;
 use crate::Square;
 use std::fmt;
@@ -17,14 +18,14 @@ impl BitBoard {
         BitBoard(bits)
     }
 
-    pub fn rank(rank: u8) -> BitBoard {
+    pub fn rank(rank: usize) -> BitBoard {
         assert!(rank < 8);
-        BitBoard(0xFF).shift_north(rank)
+        RANKS[rank]
     }
 
-    pub fn file(file: u8) -> BitBoard {
+    pub fn file(file: usize) -> BitBoard {
         assert!(file < 8);
-        BitBoard(0x0101010101010101).shift_east(file)
+        FILES[file]
     }
 
     pub fn is_empty(&self) -> bool {
diff --git a/board/src/bitboard/library.rs b/board/src/bitboard/library.rs
new file mode 100644
index 0000000..46f54b1
--- /dev/null
+++ b/board/src/bitboard/library.rs
@@ -0,0 +1,25 @@
+// Eryn Wells <eryn@erynwells.me>
+
+use super::BitBoard;
+
+pub(super) const RANKS: [BitBoard; 8] = [
+    BitBoard(0xFF << 0 * 8),
+    BitBoard(0xFF << 1 * 8),
+    BitBoard(0xFF << 2 * 8),
+    BitBoard(0xFF << 3 * 8),
+    BitBoard(0xFF << 4 * 8),
+    BitBoard(0xFF << 5 * 8),
+    BitBoard(0xFF << 6 * 8),
+    BitBoard(0xFF << 7 * 8),
+];
+
+pub(super) const FILES: [BitBoard; 8] = [
+    BitBoard(0x0101010101010101 << 0),
+    BitBoard(0x0101010101010101 << 1),
+    BitBoard(0x0101010101010101 << 2),
+    BitBoard(0x0101010101010101 << 3),
+    BitBoard(0x0101010101010101 << 4),
+    BitBoard(0x0101010101010101 << 5),
+    BitBoard(0x0101010101010101 << 6),
+    BitBoard(0x0101010101010101 << 7),
+];
diff --git a/board/src/bitboard/mod.rs b/board/src/bitboard/mod.rs
index 9bf08d1..02fd8bd 100644
--- a/board/src/bitboard/mod.rs
+++ b/board/src/bitboard/mod.rs
@@ -1,5 +1,6 @@
 mod bit_scanner;
 mod bitboard;
+mod library;
 mod shifts;
 
 pub(crate) use self::bit_scanner::BitScanner;