diff --git a/examples/lasscf_async/c2h6n4_lasscf88_sto3g.py b/examples/lasscf_async/c2h6n4_lasscf88_sto3g.py
index da3fc09c..290072f2 100644
--- a/examples/lasscf_async/c2h6n4_lasscf88_sto3g.py
+++ b/examples/lasscf_async/c2h6n4_lasscf88_sto3g.py
@@ -2,6 +2,7 @@
 from mrh.tests.lasscf.c2h6n4_struct import structure as struct
 from mrh.my_pyscf.mcscf import lasscf_sync_o0 as syn
 from mrh.my_pyscf.mcscf import lasscf_async as asyn
+from mrh.my_pyscf.mcscf.lasscf_async import old_aa_sync_kernel
 
 mol = struct (1.0, 1.0, 'sto-3g', symmetry=False)
 mol.verbose = 5
@@ -22,7 +23,17 @@
 las_asyn.max_cycle_macro = 50 # by default, all subproblems use this
 las_asyn.impurity_params['max_cycle_macro'] = 51 # all fragments
 las_asyn.impurity_params[1]['max_cycle_macro'] = 52 # second fragment only (has priority)
-las_asyn.relax_params['max_cycle_macro'] = 53
+las_asyn.relax_params['max_cycle_macro'] = 53 # "flas", the "LASCI step"
+# If you have more than two fragments, you can apply specific parameters to orbital relaxations
+# between specific pairs of fragments. Addressing specific fragment pairs has priority over
+# the global settings above.
+las_asyn.relax_params['max_cycle_micro'] = 6 # loses
+las_asyn.relax_params[(0,1)]['max_cycle_micro'] = 7 # wins
+# However, the old_aa_sync_kernel doesn't relax the active orbitals in a pairwise way, so stuff like
+# "relax_params[(0,1)]" is ignored if we patch in the old kernel:
+# 
+# las_asyn = old_aa_sync_kernel.patch_kernel (las_asyn) # uncomment me to make 6 win
+
 mo = las_asyn.set_fragments_((list (range (3)), list (range (9,12))), mf.mo_coeff)
 las_asyn.state_average_(weights=[1,0,0,0,0],
                         spins=[[0,0],[2,0],[-2,0],[0,2],[0,-2]],
diff --git a/my_pyscf/mcscf/lasscf_async/lasscf_async.py b/my_pyscf/mcscf/lasscf_async/lasscf_async.py
index 9cceded6..3c47455b 100644
--- a/my_pyscf/mcscf/lasscf_async/lasscf_async.py
+++ b/my_pyscf/mcscf/lasscf_async/lasscf_async.py
@@ -181,6 +181,8 @@ def __init__(self, mf, ncas, nelecas, ncore=None, spin_sub=None, **kwargs):
         for i in range (self.nfrags):
             self.impurity_params[i] = {}
         self.relax_params = {}
+        for i, j in itertools.combinations (range (self.nfrags), 2):
+            self.relax_params[(i,j)] = {}
         keys = set (('frags_orbs','impurity_params','relax_params'))
         self._keys = self._keys.union (keys)