diff --git a/lib/sapporo_light/sapporo.cpp b/lib/sapporo_light/sapporo.cpp
index 3ad6e5ab83..1afd0c1c4e 100644
--- a/lib/sapporo_light/sapporo.cpp
+++ b/lib/sapporo_light/sapporo.cpp
@@ -270,3 +270,8 @@ int sapporo::get_ngb_list(int cluster_id,
     sort(nbl, nbl + min(nblen, maxlength));
     return overflow;
 }
+
+int sapporo::get_nj_max() const
+{
+    return nj_max;
+}
diff --git a/lib/sapporo_light/sapporo.h b/lib/sapporo_light/sapporo.h
index cb8b60ce59..1a2469e8ef 100644
--- a/lib/sapporo_light/sapporo.h
+++ b/lib/sapporo_light/sapporo.h
@@ -103,6 +103,9 @@ extern "C"
 {
   int  get_device_count();
   cudaError_t host_evaluate_gravity(sapporo_multi_struct);
+#ifdef __cplusplus
+  int g6_get_nj_max_();
+#endif
 }
 
 class sapporo {
@@ -169,7 +172,7 @@ class sapporo {
 
     predict = false;
     nj_modified = 0;
-    
+
     device.address_j = NULL;
 
     device.t_j   = NULL;
@@ -182,6 +185,7 @@ class sapporo {
     device.acc_i = NULL;
     device.vel_i = NULL;
     device.jrk_i = NULL;
+
     
   };
   ~sapporo() {};
@@ -189,6 +193,7 @@ class sapporo {
   int open(int cluster_id);
   int close(int cluster_id);
   int get_n_pipes();
+  int get_nj_max() const;
   int set_ti(int cluster_id, double ti);
 
   int set_j_particle(int cluster_id,
diff --git a/lib/sapporo_light/sapporoG6lib.cpp b/lib/sapporo_light/sapporoG6lib.cpp
index 3aff64394f..c4c4481949 100644
--- a/lib/sapporo_light/sapporoG6lib.cpp
+++ b/lib/sapporo_light/sapporoG6lib.cpp
@@ -49,6 +49,9 @@ extern "C" {
     return grav.calc_lasthalf2(*cluster_id, *nj, *ni,
 			       index, xi, vi, *eps2, h2, acc, jerk, pot, inn);
   }
+  int g6_get_nj_max_() {
+    return grav.get_nj_max();
+  }
   
   int g6_initialize_jp_buffer_(int* cluster_id, int* buf_size) {return 0;}
   int g6_flush_jp_buffer_(int* cluster_id) {return 0;}
@@ -80,4 +83,3 @@ extern "C" {
 			     
 
 }
-
diff --git a/src/amuse_ph4/interface.cc b/src/amuse_ph4/interface.cc
index 970b9f4409..7357091895 100644
--- a/src/amuse_ph4/interface.cc
+++ b/src/amuse_ph4/interface.cc
@@ -936,3 +936,9 @@ int get_id_of_updated_particle(int index, int * index_of_particle, int * status)
     *status = jd->UpdatedParticles[index].status;
     return 0;
 }
+
+int get_nj_max(int * value)
+{
+  *value = jd->get_nj_max();
+  return 0;
+}
diff --git a/src/amuse_ph4/interface.py b/src/amuse_ph4/interface.py
index 0c9f26062c..dca15222bf 100644
--- a/src/amuse_ph4/interface.py
+++ b/src/amuse_ph4/interface.py
@@ -464,6 +464,13 @@ def recompute_timesteps():
         function.result_type = 'int32'
         return function
 
+    @legacy_function
+    def get_nj_max():
+        function = LegacyFunctionSpecification()
+        function.addParameter('nj_max', dtype='int32',
+                              direction=function.OUT)
+        function.result_type = 'int32'
+        return function
 
 class ph4(GravitationalDynamics,GravityFieldCode):
 
diff --git a/src/amuse_ph4/src/jdata.cc b/src/amuse_ph4/src/jdata.cc
index f5530ee36a..9acef22d21 100644
--- a/src/amuse_ph4/src/jdata.cc
+++ b/src/amuse_ph4/src/jdata.cc
@@ -34,6 +34,7 @@
 
 #ifdef GPU
 #include "grape.h"
+#include "sapporo.h"
 #endif
 
 // AMUSE STOPPING CONDITIONS SUPPORT
@@ -1153,3 +1154,12 @@ real jdata::get_tnext()
     int ndum;
     return sched->get_list(NULL, ndum);
 }
+
+int jdata::get_nj_max()
+{
+#ifdef GPU
+    return g6_get_nj_max_();
+#else
+    return std::numeric_limits<int>::max();
+#endif
+}
diff --git a/src/amuse_ph4/src/jdata.h b/src/amuse_ph4/src/jdata.h
index 9ec464dfb7..069bd57095 100644
--- a/src/amuse_ph4/src/jdata.h
+++ b/src/amuse_ph4/src/jdata.h
@@ -212,6 +212,7 @@ class jdata {
     void spec_output(const char *s = NULL);
     void to_com();
     real get_tnext();
+    int get_nj_max();
 
     // In gpu.cc: