diff --git a/python/damask/_crystal.py b/python/damask/_crystal.py
index 689398cf6..00c7af718 100644
--- a/python/damask/_crystal.py
+++ b/python/damask/_crystal.py
@@ -378,7 +378,7 @@ class Crystal():
         """
         _kinematics = {
             'cF': {
-                'slip' :[np.array([
+                'slip': [np.array([
                            [+0,+1,-1, +1,+1,+1],
                            [-1,+0,+1, +1,+1,+1],
                            [+1,-1,+0, +1,+1,+1],
@@ -398,7 +398,7 @@ class Crystal():
                            [+1,+0,-1, +1,+0,+1],
                            [+0,+1,+1, +0,+1,-1],
                            [+0,+1,-1, +0,+1,+1]])],
-                'twin' :[np.array([
+                'twin': [np.array([
                            [-2, 1, 1,  1, 1, 1],
                            [ 1,-2, 1,  1, 1, 1],
                            [ 1, 1,-2,  1, 1, 1],
@@ -413,7 +413,7 @@ class Crystal():
                            [-1, 1, 2, -1, 1,-1]])]
             },
             'cI': {
-                'slip' :[np.array([
+                'slip': [np.array([
                            [+1,-1,+1, +0,+1,+1],
                            [-1,-1,+1, +0,+1,+1],
                            [+1,+1,+1, +0,-1,+1],
@@ -464,7 +464,7 @@ class Crystal():
                            [+1,+1,+1, -3,+2,+1],
                            [+1,+1,-1, +3,-2,+1],
                            [+1,-1,+1, +3,+2,-1]])],
-                'twin' :[np.array([
+                'twin': [np.array([
                            [-1, 1, 1,  2, 1, 1],
                            [ 1, 1, 1, -2, 1, 1],
                            [ 1, 1,-1,  2,-1, 1],
@@ -479,7 +479,7 @@ class Crystal():
                            [ 1, 1, 1,  1, 1,-2]])]
             },
             'hP': {
-                'slip' :[np.array([
+                'slip': [np.array([
                            [+2,-1,-1,+0, +0,+0,+0,+1],
                            [-1,+2,-1,+0, +0,+0,+0,+1],
                            [-1,-1,+2,+0, +0,+0,+0,+1]]),
@@ -514,7 +514,7 @@ class Crystal():
                            [+1,+1,-2,+3, -1,-1,+2,+2],
                            [-1,+2,-1,+3, +1,-2,+1,+2],
                            [-2,+1,+1,+3, +2,-1,-1,+2]])],
-                'twin' :[np.array([
+                'twin': [np.array([
                            [-1, 0, 1, 1,  1, 0,-1, 2],   # shear = (3-(c/a)^2)/(sqrt(3) c/a) <-10.1>{10.2}
                            [ 0,-1, 1, 1,  0, 1,-1, 2],
                            [ 1,-1, 0, 1, -1, 1, 0, 2],
@@ -542,7 +542,74 @@ class Crystal():
                            [-1,-1, 2,-3, -1,-1, 2, 2],
                            [ 1,-2, 1,-3,  1,-2, 1, 2],
                            [ 2,-1,-1,-3,  2,-1,-1, 2]])]
-                },
+            },
+            'tI': {
+                'slip': [np.array([
+                           [+0,+0,+1, +1,+0,+0],
+                           [+0,+0,+1, +0,+1,+0]]),
+                         np.array([
+                           [+0,+0,+1, +1,+1,+0],
+                           [+0,+0,+1, -1,+1,+0]]),
+                         np.array([
+                           [+0,+1,+0, +1,+0,+0],
+                           [+1,+0,+0, +0,+1,+0]]),
+                         np.array([
+                           [+1,-1,+1, +1,+1,+0],
+                           [+1,-1,-1, +1,+1,+0],
+                           [-1,-1,-1, -1,+1,+0],
+                           [-1,-1,+1, -1,+1,+0]]),
+                         np.array([
+                           [+1,-1,+0, +1,+1,+0],
+                           [+1,+1,+0, +1,-1,+0]]),
+                         np.array([
+                           [+0,+1,+1, +1,+0,+0],
+                           [+0,-1,+1, +1,+0,+0],
+                           [-1,+0,+1, +0,+1,+0],
+                           [+1,+0,+1, +0,+1,+0]]),
+                         np.array([
+                           [+0,+1,+0, +0,+0,+1],
+                           [+1,+0,+0, +0,+0,+1]]),
+                         np.array([
+                           [+1,+1,+0, +0,+0,+1],
+                           [-1,+1,+0, +0,+0,+1]]),
+                         np.array([
+                           [+0,+1,-1, +0,+1,+1],
+                           [+0,-1,-1, +0,-1,+1],
+                           [-1,+0,-1, -1,+0,+1],
+                           [+1,+0,-1, +1,+0,+1]]),
+                         np.array([
+                           [+1,-1,+1, +0,+1,+1],
+                           [+1,+1,-1, +0,+1,+1],
+                           [+1,+1,+1, +0,+1,-1],
+                           [-1,+1,+1, +0,+1,-1],
+                           [+1,-1,-1, +1,+0,+1],
+                           [-1,-1,+1, +1,+0,+1],
+                           [+1,+1,+1, +1,+0,-1],
+                           [+1,-1,+1, +1,+0,-1]]),
+                         np.array([
+                           [+1,+0,+0, +0,+1,+1],
+                           [+1,+0,+0, +0,+1,-1],
+                           [+0,+1,+0, +1,+0,+1],
+                           [+0,+1,+0, +1,+0,-1]]),
+                         np.array([
+                           [+0,+1,-1, +2,+1,+1],
+                           [+0,-1,-1, +2,-1,+1],
+                           [+1,+0,-1, +1,+2,+1],
+                           [-1,+0,-1, -1,+2,+1],
+                           [+0,+1,-1, -2,+1,+1],
+                           [+0,-1,-1, -2,-1,+1],
+                           [-1,+0,-1, -1,-2,+1],
+                           [+1,+0,-1, +1,-2,+1]]),
+                         np.array([
+                           [-1,+1,+1, +2,+1,+1],
+                           [-1,-1,+1, +2,-1,+1],
+                           [+1,-1,+1, +1,+2,+1],
+                           [-1,-1,+1, -1,+2,+1],
+                           [+1,+1,+1, -2,+1,+1],
+                           [+1,-1,+1, -2,-1,+1],
+                           [-1,+1,+1, -1,-2,+1],
+                           [+1,+1,+1, +1,-2,+1]])]
+                }
         }
         master = _kinematics[self.lattice][mode]
         if self.lattice == 'hP':
diff --git a/python/tests/test_Crystal.py b/python/tests/test_Crystal.py
index 90fbdce74..9c6de965d 100644
--- a/python/tests/test_Crystal.py
+++ b/python/tests/test_Crystal.py
@@ -79,3 +79,23 @@ class TestCrystal:
                     a=a,b=b,c=c,
                     alpha=alpha,beta=beta,gamma=gamma)
         assert np.allclose(points,c.lattice_points)
+
+    @pytest.mark.parametrize('crystal,length',
+                            [(Crystal(lattice='cF'),[12,6]),
+                             (Crystal(lattice='cI'),[12,12,24]),
+                             (Crystal(lattice='hP'),[3,3,6,12,6]),
+                             (Crystal(lattice='tI',c=1.2),[2,2,2,4,2,4,2,2,4,8,4,8,8])
+                            ])
+    def test_N_slip(self,crystal,length):
+        assert [len(s) for s in crystal.kinematics('slip')['direction']] == length
+        assert [len(s) for s in crystal.kinematics('slip')['plane']] == length
+
+    @pytest.mark.parametrize('crystal,length',
+                            [(Crystal(lattice='cF'),[12]),
+                             (Crystal(lattice='cI'),[12]),
+                             (Crystal(lattice='hP'),[6,6,6,6]),
+                            ])
+    def test_N_twin(self,crystal,length):
+        assert [len(s) for s in crystal.kinematics('twin')['direction']] == length
+        assert [len(s) for s in crystal.kinematics('twin')['plane']] == length
+