diff --git a/include/noun/jets.h b/include/noun/jets.h
index a0ef42f53..36b219aff 100644
--- a/include/noun/jets.h
+++ b/include/noun/jets.h
@@ -61,23 +61,27 @@
         u3j_core* ray_u;              //  dynamic array by axis
       } u3j_dash;
 
+      /* u3j_fist: a single step in a fine check */
       typedef struct {
-        u3_noun bat;
-        u3_noun pax;
+        u3_noun bat;                  //  battery
+        u3_noun pax;                  //  parent axis
       } u3j_fist;
 
+      /* u3j_fink: (fine check) verify a located core */
       typedef struct {
-        c3_w    len_w;
-        u3_noun sat;
-        u3j_fist fis_u[0];
+        c3_w    len_w;                //  number of fists
+        u3_noun sat;                  //  static noun at end of check
+        u3j_fist fis_u[0];            //  fists
       } u3j_fink;
 
+      /* u3j_rite: site of a %fast, used to skip re-mining */
       typedef struct {
-        c3_o      own_o;
-        u3_weak   clu;
-        u3j_fink* fin_u;
+        c3_o          own_o;          //  rite owns fink?
+        u3_weak       clu;            //  cached product of clue formula
+        u3p(u3j_fink) fin_p;          //  fine check
       } u3j_rite;
 
+      /* u3j_site: site of a nock 9 */
       struct _u3n_prog;
       typedef struct {
         struct _u3n_prog *pog_u;
diff --git a/jets/b/levy.c b/jets/b/levy.c
index 76d437371..3f4978b79 100644
--- a/jets/b/levy.c
+++ b/jets/b/levy.c
@@ -31,7 +31,7 @@
   {
     u3_noun  pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _levy_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/lien.c b/jets/b/lien.c
index cede8fa83..c37b1ee8f 100644
--- a/jets/b/lien.c
+++ b/jets/b/lien.c
@@ -31,7 +31,7 @@
   {
     u3_noun  pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _lien_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/murn.c b/jets/b/murn.c
index d177137f4..e0dcb8d23 100644
--- a/jets/b/murn.c
+++ b/jets/b/murn.c
@@ -37,7 +37,7 @@
   {
     u3_noun pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _murn_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/reel.c b/jets/b/reel.c
index 474e43280..de963fe34 100644
--- a/jets/b/reel.c
+++ b/jets/b/reel.c
@@ -28,7 +28,7 @@
   {
     u3_noun  pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _reel_in(&sit_u, a, u3k(u3r_at(u3x_sam_3, b)));
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/roll.c b/jets/b/roll.c
index 448c25275..49b7eccf0 100644
--- a/jets/b/roll.c
+++ b/jets/b/roll.c
@@ -26,7 +26,7 @@
   {
     u3_noun  pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _roll_in(&sit_u, a, u3k(u3r_at(u3x_sam_3, b)));
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/skid.c b/jets/b/skid.c
index 85269436d..29ab919b0 100644
--- a/jets/b/skid.c
+++ b/jets/b/skid.c
@@ -37,7 +37,7 @@
   {
     u3_noun  pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _skid_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/skim.c b/jets/b/skim.c
index 0af438cd3..c5e721ec1 100644
--- a/jets/b/skim.c
+++ b/jets/b/skim.c
@@ -33,7 +33,7 @@
   {
     u3_noun pro;
     u3j_site sit_u;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _skim_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/skip.c b/jets/b/skip.c
index 7dc431a1f..36ff1a3e6 100644
--- a/jets/b/skip.c
+++ b/jets/b/skip.c
@@ -33,7 +33,7 @@
   {
     u3j_site sit_u;
     u3_noun  pro;
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _skip_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/jets/b/turn.c b/jets/b/turn.c
index 42ba67e6e..e183ae4bf 100644
--- a/jets/b/turn.c
+++ b/jets/b/turn.c
@@ -24,7 +24,7 @@
     u3_noun  pro;
     u3j_site sit_u;
 
-    u3j_gate_prep(&sit_u, b);
+    u3j_gate_prep(&sit_u, u3k(b));
     pro = _turn_in(&sit_u, a);
     u3j_gate_lose(&sit_u);
     return pro;
diff --git a/noun/jets.c b/noun/jets.c
index 4a6088b6e..3edce118a 100644
--- a/noun/jets.c
+++ b/noun/jets.c
@@ -1009,16 +1009,16 @@ u3j_rite_copy(u3j_rite* dst_u, u3j_rite* src_u, c3_o los_o)
 {
   if ( u3_none == src_u->clu ) {
     dst_u->clu   = u3_none;
-    dst_u->fin_u = NULL;
+    dst_u->fin_p = 0;
   }
   else {
-    u3_noun  old    = dst_u->clu;
-    u3j_fink* fon_u = dst_u->fin_u;
-    c3_o     own_o  = dst_u->own_o;
+    u3_noun   old   = dst_u->clu;
+    u3j_fink* fon_u = u3to(u3j_fink, dst_u->fin_p);
+    c3_o      own_o = dst_u->own_o;
     if ( c3y == src_u->own_o ) {
       dst_u->own_o = c3y;
       dst_u->clu   = u3a_take(src_u->clu);
-      dst_u->fin_u = _cj_fink_take(src_u->fin_u);
+      dst_u->fin_p = u3of(u3j_fink, _cj_fink_take(u3to(u3j_fink, src_u->fin_p)));
       if ( (c3y == los_o) &&
           (u3_none != old) &&
           (c3y == own_o) ) {
@@ -1280,6 +1280,7 @@ u3j_kink(u3_noun cor, u3_noun axe)
 }
 
 /* u3j_gate_prep(): prepare a locally cached gate to call repeatedly.
+ *                  core is TRANSFERRED.
  */
 void
 u3j_gate_prep(u3j_site* sit_u, u3_noun cor)
@@ -1288,9 +1289,10 @@ u3j_gate_prep(u3j_site* sit_u, u3_noun cor)
   u3t_on(glu_o);
   if ( c3n == u3du(cor) || c3n == u3du(u3t(cor)) ) {
     u3m_bail(c3__exit);
+    return;
   }
   sit_u->axe   = 2;
-  sit_u->bat   = u3k(cor); // a lie, this isn't really the battery!
+  sit_u->bat   = cor; // a lie, this isn't really the battery!
   sit_u->pog_u = _cj_prog(u3h(cor));
   if ( u3_none != (loc = sit_u->loc = _cj_spot(cor)) ) {
     u3_noun pax = u3h(u3t(loc)),
@@ -1551,15 +1553,15 @@ u3j_rite_mine(u3j_rite* rit_u, u3_noun clu, u3_noun cor)
 
   if ( non_t ||
        c3n == u3r_sing(rit_u->clu, clu) ||
-       c3n == _cj_fine(cor, rit_u->fin_u) ) {
+       c3n == _cj_fine(cor, u3to(u3j_fink, rit_u->fin_p)) ) {
     u3_weak loc = _cj_mile(u3k(clu), u3k(cor));
     if ( u3_none != loc ) {
       u3_noun   old   = rit_u->clu;
-      u3j_fink* fon_u = rit_u->fin_u;
+      u3j_fink* fon_u = u3to(u3j_fink, rit_u->fin_p);
       c3_o      own_o = rit_u->own_o;
       rit_u->own_o    = c3y;
       rit_u->clu      = u3k(clu);
-      rit_u->fin_u    = _cj_cast(cor, loc);
+      rit_u->fin_p    = u3of(u3j_fink, _cj_cast(cor, loc));
       u3z(loc);
 
       if ( !non_t && (c3y == own_o) ) {
@@ -1842,7 +1844,7 @@ u3j_rite_lose(u3j_rite* rit_u)
 {
   if ( (c3y == rit_u->own_o) && u3_none != rit_u->clu ) {
     u3z(rit_u->clu);
-    _cj_fink_free(rit_u->fin_u);
+    _cj_fink_free(u3to(u3j_fink, rit_u->fin_p));
   }
 }
 
@@ -1854,7 +1856,7 @@ u3j_rite_mark(u3j_rite* rit_u)
   c3_w tot_w = 0;
   if ( (c3y == rit_u->own_o) && u3_none != rit_u->clu ) {
     tot_w += u3a_mark_noun(rit_u->clu);
-    tot_w += _cj_fink_mark(rit_u->fin_u);
+    tot_w += _cj_fink_mark(u3to(u3j_fink, rit_u->fin_p));
   }
   return tot_w;
 }
diff --git a/noun/nock.c b/noun/nock.c
index 494ffc801..f682e1888 100644
--- a/noun/nock.c
+++ b/noun/nock.c
@@ -789,7 +789,7 @@ _n_prog_asm(u3_noun ops, u3n_prog* pog_u, u3_noun sip)
           u3j_rite* rit_u = &(pog_u->reg_u.rit_u[reg_s++]);
           rit_u->own_o = c3n;
           rit_u->clu   = u3_none;
-          rit_u->fin_u = NULL;
+          rit_u->fin_p = 0;
           break;
         }
       }