diff -r 7ffd66591afe -r a298c6637c30 src/rules/knight.c
--- a/src/rules/knight.c	Fri Mar 28 11:45:01 2014 +0100
+++ b/src/rules/knight.c	Fri Mar 28 14:32:52 2014 +0100
@@ -28,18 +28,106 @@
  */
 
 #include "knight.h"
+#include "rules.h"
+#include <math.h>
 
-_Bool knight_chkrules(Board board, Move *move) {
-    // TODO: implement
-    return FALSE;
+_Bool knight_chkrules(Move *move) {
+    int dx = abs(move->fromfile - move->tofile);
+    int dy = abs(move->fromrow - move->torow);
+    
+    return (dx == 2 && dy == 1) || (dx == 1 && dy == 2);
 }
 
-_Bool knight_isblocked(Board board, Move *move) {
-    // TODO: implement
-    return TRUE;
+static int knight_getloc_fixedrow(Board board, Move *move) {
+    int d = 3 - abs(move->fromrow - move->torow);
+    
+    if (d == 1 || d == 2) {
+        if (move->tofile < 6 &&
+            board[move->fromrow][move->tofile + d] == move->piece) {
+            if (move->fromfile == POS_UNSPECIFIED) {
+                move->fromfile = move->tofile + d;
+                return VALID_MOVE_SYNTAX;
+            } else {
+                return AMBIGUOUS_MOVE;
+            }
+        }
+        if (move->tofile > 1 &&
+            board[move->fromrow][move->tofile - d] == move->piece) {
+            if (move->fromfile == POS_UNSPECIFIED) {
+                move->fromfile = move->tofile - d;
+                return VALID_MOVE_SYNTAX;
+            } else {
+                return AMBIGUOUS_MOVE;
+            }
+        }
+    }
+    
+    return INVALID_POSITION;
 }
 
-_Bool knight_getlocation(Board board, Move *move) {
-    // TODO: implement
-    return FALSE;
+static int knight_getloc_fixedfile(Board board, Move *move) {
+    int d = 3 - abs(move->fromfile - move->tofile);
+    
+    if (d == 1 || d == 2) {
+        if (move->torow < 6 &&
+            board[move->torow + d][move->fromfile] == move->piece) {
+            if (move->fromrow == POS_UNSPECIFIED) {
+                move->fromrow = move->torow + d;
+                return VALID_MOVE_SYNTAX;
+            } else {
+                return AMBIGUOUS_MOVE;
+            }
+        }
+        if (move->torow > 1 &&
+            board[move->torow - d][move->fromfile] == move->piece) {
+            if (move->fromrow == POS_UNSPECIFIED) {
+                move->fromrow = move->torow - d;
+                return VALID_MOVE_SYNTAX;
+            } else {
+                return AMBIGUOUS_MOVE;
+            }
+        }
+    }
+    
+    return INVALID_POSITION;
 }
+
+int knight_getlocation(Board board, Move *move) {
+    
+    if (move->fromfile != POS_UNSPECIFIED) {
+        return knight_getloc_fixedfile(board, move);
+    }
+    
+    if (move->fromrow != POS_UNSPECIFIED) {
+        return knight_getloc_fixedrow(board, move);
+    }
+    
+    for (int x = -2 ; x <= 2 ; x++) {
+        if (x == 0) {
+            continue;
+        }
+        for (int y = -2 ; y <= 2 ; y++) {
+            if (y == 0 || y == x) {
+                continue;
+            }
+            uint8_t cx = move->tofile + x;
+            uint8_t cy = move->torow + y;
+
+            if (isidx(cx) && isidx(cy) && board[cy][cx] == move->piece) {
+                if (move->fromfile == POS_UNSPECIFIED
+                    && move->fromrow == POS_UNSPECIFIED) {
+                    move->fromfile = cx;
+                    move->fromrow = cy;
+                } else {
+                    return AMBIGUOUS_MOVE;
+                }
+            }
+        }
+    }
+    
+    if (move->fromfile == POS_UNSPECIFIED || move->fromrow == POS_UNSPECIFIED) {
+        return INVALID_POSITION;
+    } else {
+        return VALID_MOVE_SYNTAX;
+    }
+}