diff --git a/spacy/_transitions.pxd b/spacy/_transitions.pxd
deleted file mode 100644
index 84422a532..000000000
--- a/spacy/_transitions.pxd
+++ /dev/null
@@ -1,25 +0,0 @@
-cdef struct Transition:
-    int clas
-    int move
-    int label
-
-    weight_t score
-    int cost
-
-    int (*get_cost)(const Transition* self, const State* state, const TokenC* gold) except -1
-
-    int (*is_valid)(const Transition* self, const State* state) except -1
-    
-    int (*do)(const Transition* self, State* state) except -1
-
-
-cdef class TransitionSystem:
-    cdef readonly dict label_ids
-    cdef Pool mem
-    cdef const Transition* c
-
-    cdef const Transition best_valid(self, const weight_t*, const State*) except *
-
-    cdef const Transition best_gold(self, const weight_t*, const State*,
-                                    const TokenC*) except *
-
diff --git a/spacy/_transitions.pyx b/spacy/_transitions.pyx
deleted file mode 100644
index 4bcb177ee..000000000
--- a/spacy/_transitions.pyx
+++ /dev/null
@@ -1,44 +0,0 @@
-from cymem.cymem cimport Pool
-from ._state cimport State
-from ..structs cimport TokenC
-from thinc.typedefs cimport weight_t
-
-
-cdef weight_t MIN_SCORE = -90000
-
-cdef class TransitionSystem:
-    cdef Pool mem
-    cdef const Transition* c
-
-    def __init__(self, dict move_types):
-        entries = []
-        for move, labels in move_types.items():
-            entries.extend((move, label) for label in labels)
-        entries.sort()
-        moves = <Transition*>self.mem.alloc(len(entries), sizeof(Transition))
-        for i, (move, label_str) in enumerate(entries):
-            moves[i].move = move
-            moves[i].label = self.label_ids.setdefault(label_str, len(self.label_ids))
-            moves[i].clas
-    
-    cdef const Transition best_valid(self, const weight_t* scores,
-                                     const State* s) except *:
-        cdef int best = -1
-        cdef weight_t score = MIN_SCORE
-        cdef int i
-        for i in range(self.n_moves):
-            if scores[i] > score and self.c[i].is_valid(&self.c[i], s):
-                best = i
-                score = scores[i]
-        return self.c[best]
-
-    cdef const Transition best_gold(self, const weight_t* scores, const State* s,
-                                    const TokenC* gold) except *:
-        cdef int best = -1
-        cdef weight_t score = MIN_SCORE
-        cdef int i
-        for i in range(self.n_moves):
-            if scores[i] > score and self.c[i].get_cost(&self.c[i], s, gold) == 0:
-                best = i
-                score = scores[i]
-        return self.c[best]