diff --git a/src/main/java/de/tims/fleetstorm/ai/Logic.java b/src/main/java/de/tims/fleetstorm/ai/Logic.java
index e80125d..668984b 100644
--- a/src/main/java/de/tims/fleetstorm/ai/Logic.java
+++ b/src/main/java/de/tims/fleetstorm/ai/Logic.java
@@ -11,11 +11,12 @@ public class Logic {
 	private Matchfield matchfield;
 	private Coordinate lastShot;
 
-	public Coordinate chooseField(Matchfield matchfield) {
+	public Coordinate chooseField() {
 		ArrayList<Coordinate> possibleFields = new ArrayList<Coordinate>();
-		for (int x = 0; x < Math.sqrt(matchfield.getSize()); x++) {
-			for (int y = 0; y < Math.sqrt(matchfield.getSize()); y++) {
-				if (matchfield.getState(x, y) == Coordinate.EMPTY || matchfield.getState(x, y) == Coordinate.SHIP) {
+		for (int x = 0; x < Math.sqrt(this.matchfield.getSize()); x++) {
+			for (int y = 0; y < Math.sqrt(this.matchfield.getSize()); y++) {
+				if (this.matchfield.getState(x, y) == Coordinate.EMPTY
+						|| this.matchfield.getState(x, y) == Coordinate.SHIP) {
 					possibleFields.add(new Coordinate(x, y));
 				}
 			}
diff --git a/src/test/java/de/tims/fleetstorm/ai/LogicTest.java b/src/test/java/de/tims/fleetstorm/ai/LogicTest.java
index 0c47f54..440710d 100644
--- a/src/test/java/de/tims/fleetstorm/ai/LogicTest.java
+++ b/src/test/java/de/tims/fleetstorm/ai/LogicTest.java
@@ -20,7 +20,8 @@ class LogicTest {
 		int size = 5;
 		matchfield = new Matchfield(size);
 		matchfield.createMatchfield();
-		Coordinate calcResult = logic.chooseField(matchfield);
+		logic.setMatchfield(matchfield);
+		Coordinate calcResult = logic.chooseField();
 		assertNotNull(calcResult);
 	}
 
@@ -31,6 +32,7 @@ class LogicTest {
 		int size = 5;
 		matchfield = new Matchfield(size);
 		matchfield.createMatchfield();
+		logic.setMatchfield(matchfield);
 
 		for (int x = 0; x < size; x++) {
 			for (int y = 0; y < size; y++) {
@@ -39,7 +41,7 @@ class LogicTest {
 		}
 		matchfield.setState(2, 2, Coordinate.EMPTY);
 
-		Coordinate choosenField = logic.chooseField(matchfield);
+		Coordinate choosenField = logic.chooseField();
 		int calcState = matchfield.getState(choosenField.getX(), choosenField.getY());
 		assertNotEquals(calcState, Coordinate.SHOT);
 	}