diff --git a/make.deps b/make.deps
index 7fa7bce..1df5635 100644
--- a/make.deps
+++ b/make.deps
@@ -1,10 +1,10 @@
 ./obj/debug.o:: src/debug.c src/debug.h
 ./obj/fen.o:: src/fen.c src/debug.h src/chessdefs.h src/position.h src/board.h \
- src/list.h src/fen.h src/piece.h src/pool.h
-./obj/move.o:: src/move.c src/chessdefs.h src/piece.h src/board.h src/list.h \
- src/position.h src/pool.h src/move.h
-./obj/piece.o:: src/piece.c src/chessdefs.h src/piece.h src/board.h src/list.h \
- src/position.h src/pool.h src/debug.h
+ src/piece.h src/list.h src/pool.h src/fen.h
+./obj/move.o:: src/move.c src/chessdefs.h src/piece.h src/board.h src/position.h \
+ src/list.h src/pool.h src/move.h
+./obj/piece.o:: src/piece.c src/chessdefs.h src/piece.h src/board.h \
+ src/position.h src/list.h src/pool.h src/debug.h
 ./obj/pool.o:: src/pool.c src/list.h src/pool.h src/debug.h
 ./obj/position.o:: src/position.c src/chessdefs.h src/position.h src/board.h \
- src/list.h src/fen.h src/piece.h src/pool.h
+ src/piece.h src/list.h src/pool.h src/fen.h
diff --git a/src/board.h b/src/board.h
index d0cdff4..98a08e8 100644
--- a/src/board.h
+++ b/src/board.h
@@ -16,10 +16,12 @@
 
 #include <stdint.h>
 #include "chessdefs.h"
+#include "piece.h"
+#include "position.h"
 
-typedef struct {
+typedef struct board_s {
     piece_t piece;
-    //piece_t *s_piece;
+    piece_list_t *s_piece;
 } board_t;                                        /* 0x88 board */
 #define BOARDSIZE    (8*8*2)
 
@@ -51,4 +53,4 @@ typedef struct {
 #define FILE2C(f)    ((f) + 'a')
 #define RANK2C(r)    ((r) + '1')
 
-#endif
+#endif  /* BOARD_H */
diff --git a/src/chessdefs.h b/src/chessdefs.h
index 12db0cd..c833983 100644
--- a/src/chessdefs.h
+++ b/src/chessdefs.h
@@ -73,4 +73,10 @@ typedef unsigned char castle_t;
  */
 typedef int64_t         eval_t;
 
+/* forward typedefs
+ */
+typedef struct piece_list_s piece_list_t;
+typedef struct board_s board_t;
+typedef struct pos_s pos_t;
+
 #endif
diff --git a/src/fen.c b/src/fen.c
index f3e0cf4..2b8014f 100644
--- a/src/fen.c
+++ b/src/fen.c
@@ -84,7 +84,7 @@ pos_t *fen2pos(pos_t *pos, char *fen)
 #               endif
                 piece |= color;
                 board[SQ88(file, rank)].piece = piece;
-                piece_add(pos, piece, SQUARE(file, rank));
+                board[SQ88(file, rank)].s_piece = piece_add(pos, piece, SQUARE(file, rank));
                 file++;
                 break;
             case '/':
diff --git a/src/piece.h b/src/piece.h
index 2c5bde2..1536776 100644
--- a/src/piece.h
+++ b/src/piece.h
@@ -14,12 +14,13 @@
 #ifndef PIECE_H
 #define PIECE_H
 
+#include <ctype.h>
+
 #include "chessdefs.h"
 #include "board.h"
 #include "list.h"
 #include "position.h"
 #include "pool.h"
-#include "ctype.h"
 
 #define PIECE_DEFAULT_VALUE 0
 
@@ -31,7 +32,7 @@
 #define QUEEN_VALUE   900
 #define KING_VALUE    20000
 
-typedef struct {
+typedef struct piece_list_s {
     piece_t piece;
     square_t square;
     short castle;
diff --git a/src/position.h b/src/position.h
index 5e0a7e5..2e3ad65 100644
--- a/src/position.h
+++ b/src/position.h
@@ -19,7 +19,7 @@
 #include "board.h"
 #include "list.h"
 
-typedef struct position {
+typedef struct pos_s {
     piece_t turn;                                 /* we use only color bit */
     castle_t castle;
     square_t en_passant;