diff --git a/.vscode/settings.json b/.vscode/settings.json
index 604d63d..8431ee7 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,7 +1,8 @@
 {
 	"files.associations": {
 		"game_ext.h": "c",
-		"game.h": "c"
+		"game.h": "c",
+		"game_private.h": "c"
 	},
 	"editor.formatOnSave": true,
 	"C_Cpp.clang_format_path": "/usr/bin/clang-format"
diff --git a/game.c b/game.c
index 40543b7..7c2ac5c 100644
--- a/game.c
+++ b/game.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "game_ext.h"
+#include "game_private.h"
 
 int max(int a, int b) {
 	if (a > b)
@@ -50,7 +51,6 @@ game game_new_empty(void) {
 	g->hist = history_insert_first(g->hist, F_ERROR, 0, 0);
 	return g;
 }
-// TODO
 game game_copy(cgame g1) {
 	game g2 = game_new_empty_ext(g1->height, g1->width, g1->wrapping);
 	for (int i = 0; i < g2->height; i++) {
diff --git a/game.h b/game.h
index f1c54d2..4c0ecb0 100644
--- a/game.h
+++ b/game.h
@@ -7,11 +7,12 @@
 
 #ifndef __GAME_H__
 #define __GAME_H__
+
 #include <stdbool.h>
+
 /**
  * @brief Standard unsigned integer type.
  **/
-
 typedef unsigned int uint;
 
 /**
@@ -57,15 +58,6 @@ typedef enum {
 /** square mask used in square enum */
 #define A_MASK 0xFF
 
-#include "history.h"
-struct game_s {
-	square** tab_cell;
-	bool wrapping;
-	uint height;  // i in general
-	uint width;   // j in general
-	history hist;
-};
-
 /**
  * @brief The structure pointer that stores the game state.
  **/
@@ -217,6 +209,8 @@ bool game_is_black(cgame g, uint i, uint j);
  * @pre @p g must be a valid pointer toward a game structure.
  * @pre @p i < game height
  * @pre @p j < game width
+ * @pre The square at position (i,j) must be a black wall (either numbered or
+ * unumbered).
  * @return the back wall number, or -1 if it is unumbered
  **/
 int game_get_black_number(cgame g, uint i, uint j);
@@ -319,4 +313,4 @@ bool game_is_over(cgame g);
  **/
 void game_restart(game g);
 
-#endif  // __GAME_H__
+#endif  // __GAME_H__
\ No newline at end of file
diff --git a/game_aux.c b/game_aux.c
index 76a4335..6dd606f 100644
--- a/game_aux.c
+++ b/game_aux.c
@@ -1,6 +1,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include "game.h"
+#include "game_private.h"
 
 char charPrintCell(cgame g, uint i, uint j) {
 	square sqState = game_get_state(g, i, j);
diff --git a/game_aux.h b/game_aux.h
index 294f997..1e425a6 100644
--- a/game_aux.h
+++ b/game_aux.h
@@ -8,6 +8,7 @@
 #ifndef __GAME_AUX_H__
 #define __GAME_AUX_H__
 #include <stdbool.h>
+
 #include "game.h"
 
 /**
@@ -35,4 +36,4 @@ game game_default(void);
  **/
 game game_default_solution(void);
 
-#endif  // __GAME_AUX_H__
+#endif  // __GAME_AUX_H__
\ No newline at end of file
diff --git a/game_ext.c b/game_ext.c
index 6dd5270..8f8e486 100644
--- a/game_ext.c
+++ b/game_ext.c
@@ -1,6 +1,7 @@
 #include "game_ext.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include "game_private.h"
 
 game game_new_ext(uint nb_rows, uint nb_cols, square* squares, bool wrapping) {
 	game g = game_new_empty_ext(nb_rows, nb_cols, wrapping);
@@ -37,7 +38,7 @@ game game_new_empty_ext(uint nb_rows, uint nb_cols, bool wrapping) {
 			exit(EXIT_FAILURE);
 		}
 	}
-	g->hist = history_insert_first(g->hist,F_ERROR,0,0);
+	g->hist = history_insert_first(g->hist, F_ERROR, 0, 0);
 	return g;
 }
 
diff --git a/game_private.h b/game_private.h
new file mode 100644
index 0000000..462e29e
--- /dev/null
+++ b/game_private.h
@@ -0,0 +1,13 @@
+#ifndef __GAME_PRIVATE_H__
+#define __GAME_PRIVATE_H__
+#include "history.h"
+
+struct game_s {
+	square** tab_cell;
+	bool wrapping;
+	uint height;  // i in general
+	uint width;   // j in general
+	history hist;
+};
+
+#endif
\ No newline at end of file
diff --git a/game_test_nnunes.c b/game_test_nnunes.c
index 8d313c1..ef72fec 100644
--- a/game_test_nnunes.c
+++ b/game_test_nnunes.c
@@ -6,6 +6,7 @@
 #include "game.h"
 #include "game_aux.h"
 #include "game_ext.h"
+#include "game_private.h"
 
 bool test_dummy(void) {
 	return true;
@@ -410,7 +411,7 @@ int main(int argc, char* argv[]) {
 	} else if (strcmp("game_nb_cols", argv[1]) == 0) {
 		success = test_game_nb_cols();
 	} else if (strcmp("game_is_wrapping", argv[1]) == 0) {
-		success = test_game_is_wrapping();						
+		success = test_game_is_wrapping();
 	} else {
 		fprintf(stderr, "Error: test \"%s\" not found!\n", argv[1]);
 		exit(EXIT_FAILURE);
diff --git a/game_test_thoguet.c b/game_test_thoguet.c
index 46e9821..8534665 100644
--- a/game_test_thoguet.c
+++ b/game_test_thoguet.c
@@ -6,6 +6,8 @@
 #include "game.h"
 #include "game_aux.h"
 #include "game_ext.h"
+#include "game_private.h"
+
 typedef unsigned int uint;
 
 /* ********** DUMMY ********** */
diff --git a/game_test_thperrier.c b/game_test_thperrier.c
index 65ac3dd..50e4749 100644
--- a/game_test_thperrier.c
+++ b/game_test_thperrier.c
@@ -6,6 +6,7 @@
 #include "game.h"
 #include "game_aux.h"
 #include "game_ext.h"
+#include "game_private.h"
 
 /* ********** DUMMY ********** */
 bool test_dummy() {
diff --git a/game_text.c b/game_text.c
index 8621ed1..3e66832 100644
--- a/game_text.c
+++ b/game_text.c
@@ -4,6 +4,7 @@
 #include "game.h"
 #include "game_aux.h"
 #include "game_ext.h"
+#include "game_private.h"
 
 bool checkerr(cgame g, char taberr[]) {
 	if (taberr == NULL || g == NULL) {
@@ -78,7 +79,7 @@ int main(int argc, char* argv[]) {
 		printf("Entrez une commande (h pour afficher l'aide): ");
 		if (scanf(" %c", &c)) {
 			if (c == 'h') {
-				printhelp();				
+				printhelp();
 			} else if (c == 'r') {
 				game_restart(g);
 				printf("Partie réinitialisé avec succes !\n");