diff --git a/Sudoku/JTextFieldCharLimit.java b/Sudoku/JTextFieldCharLimit.java
new file mode 100644
index 0000000..fc35118
--- /dev/null
+++ b/Sudoku/JTextFieldCharLimit.java
@@ -0,0 +1,18 @@
+import javax.swing.text.PlainDocument;
+import javax.swing.text.AttributeSet;
+import javax.swing.text.BadLocationException;
+
+public class JTextFieldCharLimit extends PlainDocument{
+	private int limit; 
+
+	public JTextFieldCharLimit(int limit){
+		this.limit = limit;
+	}
+	public void insertString(int offset, String str, AttributeSet set) throws BadLocationException{
+		if (str == null){
+			return;
+		} else if ((getLength() + str.length() - getLength()) <= limit){
+			super.insertString(offset, str, set);
+		}
+	}
+}
\ No newline at end of file
diff --git a/Sudoku/grille.java b/Sudoku/grille.java
index a0e2a0d..0c8d884 100644
--- a/Sudoku/grille.java
+++ b/Sudoku/grille.java
@@ -4,7 +4,11 @@ import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.io.*;
 import javax.swing.border.Border;
-import javax.swing.text.*;
+import javax.swing.text.PlainDocument;
+import javax.swing.text.AttributeSet;
+import javax.swing.text.BadLocationException;
+
+
 
 public class grille extends JComponent{
 	private static JLabel etat_exportation = new JLabel();
@@ -33,6 +37,13 @@ public class grille extends JComponent{
 		if(editable){
 			JTextField[][] case_editable = null;
 			case_editable = new JTextField[9][9];
+			for (int ligne = 0; ligne < 9; ligne++) {
+		        for (int col = 0; col < 9; col++) {
+					case_editable[ligne][col] = new JTextField();
+		        	case_editable[ligne][col].setDocument(new JTextFieldCharLimit(4));
+		        }
+		    }
+
 			for (int ligne = 0; ligne < 9; ligne++) {
 		        for (int col = 0; col < 9; col++) {
 		        	if (grille[ligne][col] == 0){
@@ -61,10 +72,12 @@ public class grille extends JComponent{
 			JLabel[][] case_depart = null;
 			case_depart = new JLabel[9][9];
 			case_modifiable = new JTextField[9][9];
-
+			
 		    for (int ligne = 0; ligne < 9; ligne++) {
 		        for (int col = 0; col < 9; col++) {
 		            if ((grid_values[ligne][col]) == 0) {
+
+		       			case_modifiable[ligne][col].setDocument(new JTextFieldCharLimit(4));
 			            case_modifiable[ligne][col] = new JTextField("", 1);
 			            case_modifiable[ligne][col].setFont(new Font("Arial", Font.PLAIN, 30));
 			            case_modifiable[ligne][col].setHorizontalAlignment(JTextField.CENTER);