diff --git a/spacy/syntax/parser.pyx b/spacy/syntax/parser.pyx
index d53a1959a..ed89d4cc8 100644
--- a/spacy/syntax/parser.pyx
+++ b/spacy/syntax/parser.pyx
@@ -172,12 +172,32 @@ cdef class StepwiseState:
         return self.parser.moves.move_name(action.move, action.label)
 
     def transition(self, action_name):
+        moves = {'S': 0, 'D': 1, 'L': 2, 'R': 3}
         if action_name == '_':
             action_name = self.predict()
-        action = self.parser.moves.lookup_transition(action_name)
+        if action_name == 'L' or action_name == 'R':
+            self.predict()
+            move = moves[action_name]
+            clas = _arg_max_clas(self.eg.c.scores, move, self.parser.moves.c,
+                                 self.eg.c.nr_class)
+            action = self.parser.moves.c[clas]
+        else:
+            action = self.parser.moves.lookup_transition(action_name)
         action.do(self.stcls, action.label)
 
     def finish(self):
         if self.stcls.is_final():
             self.parser.moves.finalize_state(self.stcls)
         self.doc.set_parse(self.stcls._sent)
+
+
+cdef int _arg_max_clas(const weight_t* scores, int move, const Transition* actions,
+                       int nr_class) except -1:
+    cdef weight_t score = 0
+    cdef int mode = -1
+    cdef int i
+    for i in range(nr_class):
+        if actions[i].move == move and (mode == -1 or scores[i] >= score):
+            mode = actions[i].clas
+            score = scores[i]
+    return mode