diff --git a/src/coins.cpp b/src/coins.cpp
index f2999df13..0145c225f 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -914,7 +914,7 @@ CAmount CCoinsViewCache::GetValueIn(const CTransaction& tx) const
     return nResult;
 }
 
-bool CCoinsViewCache::HaveShieldedRequirements(const CTransaction& tx) const
+std::optional<UnsatisfiedShieldedReq> CCoinsViewCache::HaveShieldedRequirements(const CTransaction& tx) const
 {
     boost::unordered_map<uint256, SproutMerkleTree, CCoinsKeyHasher> intermediates;
 
@@ -925,7 +925,7 @@ bool CCoinsViewCache::HaveShieldedRequirements(const CTransaction& tx) const
             if (GetNullifier(nullifier, SPROUT)) {
                 // If the nullifier is set, this transaction
                 // double-spends!
-                return false;
+                return UnsatisfiedShieldedReq::SproutDuplicateNullifier;
             }
         }
 
@@ -934,7 +934,7 @@ bool CCoinsViewCache::HaveShieldedRequirements(const CTransaction& tx) const
         if (it != intermediates.end()) {
             tree = it->second;
         } else if (!GetSproutAnchorAt(joinsplit.anchor, tree)) {
-            return false;
+            return UnsatisfiedShieldedReq::SproutUnknownAnchor;
         }
 
         BOOST_FOREACH(const uint256& commitment, joinsplit.commitments)
@@ -946,16 +946,17 @@ bool CCoinsViewCache::HaveShieldedRequirements(const CTransaction& tx) const
     }
 
     for (const SpendDescription &spendDescription : tx.vShieldedSpend) {
-        if (GetNullifier(spendDescription.nullifier, SAPLING)) // Prevent double spends
-            return false;
+        if (GetNullifier(spendDescription.nullifier, SAPLING)) { // Prevent double spends
+            return UnsatisfiedShieldedReq::SaplingDuplicateNullifier;
+        }
 
         SaplingMerkleTree tree;
         if (!GetSaplingAnchorAt(spendDescription.anchor, tree)) {
-            return false;
+            return UnsatisfiedShieldedReq::SaplingUnknownAnchor;
         }
     }
 
-    return true;
+    return std::nullopt;
 }
 
 bool CCoinsViewCache::HaveInputs(const CTransaction& tx) const
diff --git a/src/coins.h b/src/coins.h
index 10999e8d9..67cba90e8 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -447,6 +447,14 @@ public:
     friend class CCoinsViewCache;
 };
 
+/** The set of shielded requirements that might be unsatisfied. */
+enum class UnsatisfiedShieldedReq {
+    SproutDuplicateNullifier,
+    SproutUnknownAnchor,
+    SaplingDuplicateNullifier,
+    SaplingUnknownAnchor,
+};
+
 /** CCoinsView that adds a memory cache for transactions to another CCoinsView */
 class CCoinsViewCache : public CCoinsViewBacked
 {
@@ -566,7 +574,7 @@ public:
     bool HaveInputs(const CTransaction& tx) const;
 
     //! Check whether all joinsplit and sapling spend requirements (anchors/nullifiers) are satisfied
-    bool HaveShieldedRequirements(const CTransaction& tx) const;
+    std::optional<UnsatisfiedShieldedReq> HaveShieldedRequirements(const CTransaction& tx) const;
 
     //! Return priority of tx at height nHeight
     double GetPriority(const CTransaction &tx, int nHeight) const;
diff --git a/src/main.cpp b/src/main.cpp
index 2d43a1263..4fe2df808 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -117,6 +117,28 @@ const string strMessageMagic = "Zcash Signed Message:\n";
 // Internal stuff
 namespace {
 
+    unsigned char ShieldedReqRejectCode(UnsatisfiedShieldedReq shieldedReq)
+    {
+        switch (shieldedReq) {
+            case UnsatisfiedShieldedReq::SproutDuplicateNullifier:
+            case UnsatisfiedShieldedReq::SaplingDuplicateNullifier:
+                return REJECT_DUPLICATE;
+            case UnsatisfiedShieldedReq::SproutUnknownAnchor:
+            case UnsatisfiedShieldedReq::SaplingUnknownAnchor:
+                return REJECT_INVALID;
+        }
+    }
+
+    std::string ShieldedReqRejectReason(UnsatisfiedShieldedReq shieldedReq)
+    {
+        switch (shieldedReq) {
+            case UnsatisfiedShieldedReq::SproutDuplicateNullifier:  return "bad-txns-sprout-duplicate-nullifier";
+            case UnsatisfiedShieldedReq::SproutUnknownAnchor:       return "bad-txns-sprout-unknown-anchor";
+            case UnsatisfiedShieldedReq::SaplingDuplicateNullifier: return "bad-txns-sapling-duplicate-nullifier";
+            case UnsatisfiedShieldedReq::SaplingUnknownAnchor:      return "bad-txns-sapling-unknown-anchor";
+        }
+    }
+
     /** Abort with a message */
     bool AbortNode(const std::string& strMessage, const std::string& userMessage="")
     {
@@ -1542,10 +1564,14 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
             return state.Invalid(error("AcceptToMemoryPool: inputs already spent"),
                                  REJECT_DUPLICATE, "bad-txns-inputs-spent");
 
-        // are the joinsplits' and sapling spends' requirements met in tx(valid anchors/nullifiers)?
-        if (!view.HaveShieldedRequirements(tx))
-            return state.Invalid(error("AcceptToMemoryPool: shielded requirements not met"),
-                                 REJECT_DUPLICATE, "bad-txns-shielded-requirements-not-met");
+        // Are the shielded spends' requirements met?
+        auto unmetShieldedReq = view.HaveShieldedRequirements(tx);
+        if (unmetShieldedReq) {
+            auto rejectCode = ShieldedReqRejectCode(*unmetShieldedReq);
+            auto rejectReason = ShieldedReqRejectReason(*unmetShieldedReq);
+            return state.Invalid(error("AcceptToMemoryPool: shielded requirements not met (%s)", rejectReason),
+                                 rejectCode, rejectReason);
+        }
 
         // Bring the best block into scope
         view.GetBestBlock();
@@ -2176,9 +2202,14 @@ bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoins
         if (!inputs.HaveInputs(tx))
             return state.Invalid(error("CheckInputs(): %s inputs unavailable", tx.GetHash().ToString()));
 
-        // are the JoinSplit's requirements met?
-        if (!inputs.HaveShieldedRequirements(tx))
-            return state.Invalid(error("CheckInputs(): %s JoinSplit requirements not met", tx.GetHash().ToString()));
+        // Are the shielded spends' requirements met?
+        auto unmetShieldedReq = inputs.HaveShieldedRequirements(tx);
+        if (unmetShieldedReq) {
+            auto rejectCode = ShieldedReqRejectCode(*unmetShieldedReq);
+            auto rejectReason = ShieldedReqRejectReason(*unmetShieldedReq);
+            return state.Invalid(error("CheckInputs(): %s shielded requirements not met (%s)", tx.GetHash().ToString(), rejectReason),
+                                 rejectCode, rejectReason);
+        }
 
         CAmount nValueIn = 0;
         CAmount nFees = 0;
@@ -2861,10 +2892,14 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
                 return state.DoS(100, error("ConnectBlock(): inputs missing/spent"),
                                  REJECT_INVALID, "bad-txns-inputs-missingorspent");
 
-            // are the JoinSplit's requirements met?
-            if (!view.HaveShieldedRequirements(tx))
-                return state.DoS(100, error("ConnectBlock(): JoinSplit requirements not met"),
-                                 REJECT_INVALID, "bad-txns-joinsplit-requirements-not-met");
+            // Are the shielded spends' requirements met?
+            auto unmetShieldedReq = view.HaveShieldedRequirements(tx);
+            if (unmetShieldedReq) {
+                auto rejectCode = ShieldedReqRejectCode(*unmetShieldedReq);
+                auto rejectReason = ShieldedReqRejectReason(*unmetShieldedReq);
+                return state.DoS(100, error("ConnectBlock(): shielded requirements not met (%s)", rejectReason),
+                                 rejectCode, rejectReason);
+            }
 
             // insightexplorer
             // https://github.com/bitpay/bitcoin/commit/017f548ea6d89423ef568117447e61dd5707ec42#diff-7ec3c68a81efff79b6ca22ac1f1eabbaR2597