diff --git a/include/bitcoin/database/impl/query/address/address_history.ipp b/include/bitcoin/database/impl/query/address/address_history.ipp
index ad8153fd7..75924e576 100644
--- a/include/bitcoin/database/impl/query/address/address_history.ipp
+++ b/include/bitcoin/database/impl/query/address/address_history.ipp
@@ -135,7 +135,8 @@ history CLASS::get_tx_history(hash_digest&& key, const tx_link& link,
     auto height = history::unrooted_height;
     auto position = history::unconfirmed_position;
 
-    const auto block = find_strong(link);
+    tx_link strong{};
+    const auto block = find_strong(strong, link);
     const auto at = get_confirmed_height(block);
     if (at.is_terminal())
     {
@@ -153,7 +154,7 @@ history CLASS::get_tx_history(hash_digest&& key, const tx_link& link,
     else
     {
         height = at.value;
-        if (!get_tx_position(position, link, block))
+        if (!get_tx_position(position, strong, block))
             return {};
     }
 
@@ -176,7 +177,8 @@ history CLASS::get_tx_confirmed_history(hash_digest&& key, const tx_link& link,
     if (link.is_terminal())
         return {};
 
-    const auto block = find_strong(link);
+    tx_link strong{};
+    const auto block = find_strong(strong, link);
     const auto at = get_confirmed_height(block);
 
     // Invalid with unconfirmed_position signals no fault.
@@ -184,7 +186,7 @@ history CLASS::get_tx_confirmed_history(hash_digest&& key, const tx_link& link,
         return { .position = history::unconfirmed_position };
 
     size_t position{};
-    if (!get_tx_position(position, link, block))
+    if (!get_tx_position(position, strong, block))
         return {};
 
     // Electrum uses fees only on unconfirmed (expensive).
diff --git a/include/bitcoin/database/impl/query/address/address_unspent.ipp b/include/bitcoin/database/impl/query/address/address_unspent.ipp
index ea5d2530b..c612e1eb9 100644
--- a/include/bitcoin/database/impl/query/address/address_unspent.ipp
+++ b/include/bitcoin/database/impl/query/address/address_unspent.ipp
@@ -126,12 +126,13 @@ unspent_output CLASS::get_tx_unspent(const output_link& link) const NOEXCEPT
     auto height = unspent_output::unused_height;
     auto position = unspent_output::unconfirmed_position;
 
-    const auto block = find_strong(tx);
+    tx_link strong{};
+    const auto block = find_strong(strong, tx);
     const auto at = get_confirmed_height(block);
     if (!at.is_terminal())
     {
         height = at.value;
-        if (!get_tx_position(position, tx, block))
+        if (!get_tx_position(position, strong, block))
             return {};
     }
 
@@ -147,7 +148,8 @@ unspent_output CLASS::get_tx_confirmed_unspent(const output_link& link) const NO
         return {};
 
     const auto tx = out.parent_fk;
-    const auto block = find_strong(tx);
+    tx_link strong{};
+    const auto block = find_strong(strong, tx);
     const auto at = get_confirmed_height(block);
 
     // Invalid with unconfirmed_position signals no fault.
@@ -158,7 +160,7 @@ unspent_output CLASS::get_tx_confirmed_unspent(const output_link& link) const NO
     auto hash = get_tx_key(tx);
     const auto index = to_output_index(tx, link);
     if ((index == point::null_index) || (hash == system::null_hash) ||
-        !get_tx_position(position, tx, block))
+        !get_tx_position(position, strong, block))
         return {};
 
     return { { { std::move(hash), index }, out.value }, at.value, position };
diff --git a/include/bitcoin/database/impl/query/consensus/consensus_strong.ipp b/include/bitcoin/database/impl/query/consensus/consensus_strong.ipp
index 733cd79d6..3ab1b7d72 100644
--- a/include/bitcoin/database/impl/query/consensus/consensus_strong.ipp
+++ b/include/bitcoin/database/impl/query/consensus/consensus_strong.ipp
@@ -82,21 +82,44 @@ height_link CLASS::find_strong_spender_height(
 
 TEMPLATE
 header_link CLASS::find_strong(const tx_link& link) const NOEXCEPT
+{
+    tx_link unused{};
+    return find_strong(unused, link);
+}
+
+TEMPLATE
+header_link CLASS::find_strong(tx_link& out, const tx_link& link) const NOEXCEPT
 {
     // Shortcuircuit hash-based search by testing self.
     if (const auto fk = to_block(link); !fk.is_terminal())
+    {
+        out = link;
         return fk;
+    }
 
-    return find_strong(get_tx_key(link));
+    return find_strong(out, get_tx_key(link));
 }
 
 TEMPLATE
 header_link CLASS::find_strong(const hash_digest& tx_hash) const NOEXCEPT
 {
-    // Find the first strong tx of the set and return its block.
+    tx_link unused{};
+    return find_strong(unused, tx_hash);
+}
+
+TEMPLATE
+header_link CLASS::find_strong(tx_link& out,
+    const hash_digest& tx_hash) const NOEXCEPT
+{
+    // Find the first strong tx of the set and return it with its block.
     for (const auto& tx: to_duplicates(tx_hash))
+    {
         if (const auto block = to_block(tx); !block.is_terminal())
+        {
+            out = tx;
             return block;
+        }
+    }
 
     return {};
 }
diff --git a/include/bitcoin/database/impl/query/properties_tx.ipp b/include/bitcoin/database/impl/query/properties_tx.ipp
index 1248ee655..e94a9fbc8 100644
--- a/include/bitcoin/database/impl/query/properties_tx.ipp
+++ b/include/bitcoin/database/impl/query/properties_tx.ipp
@@ -72,7 +72,9 @@ bool CLASS::get_tx_height(size_t& out, const tx_link& link) const NOEXCEPT
 TEMPLATE
 bool CLASS::get_tx_position(size_t& out, const tx_link& link) const NOEXCEPT
 {
-    return get_tx_position(out, link, find_strong(link));
+    tx_link strong{};
+    const auto block = find_strong(strong, link);
+    return get_tx_position(out, strong, block);
 }
 
 TEMPLATE
diff --git a/include/bitcoin/database/query.hpp b/include/bitcoin/database/query.hpp
index 3cc6c7551..02236a99d 100644
--- a/include/bitcoin/database/query.hpp
+++ b/include/bitcoin/database/query.hpp
@@ -355,6 +355,9 @@ class query
     tx_link find_strong_tx(const hash_digest& tx_hash) const NOEXCEPT;
     header_link find_strong(const tx_link& link) const NOEXCEPT;
     header_link find_strong(const hash_digest& tx_hash) const NOEXCEPT;
+    header_link find_strong(tx_link& out, const tx_link& link) const NOEXCEPT;
+    header_link find_strong(tx_link& out,
+        const hash_digest& tx_hash) const NOEXCEPT;
     height_link find_strong_spender_height(const point& point) const NOEXCEPT;
 
     header_link to_parent(const header_link& link) const NOEXCEPT;
diff --git a/test/query/address/address_balance.cpp b/test/query/address/address_balance.cpp
index 25d0a879c..9d2a14bf1 100644
--- a/test/query/address/address_balance.cpp
+++ b/test/query/address/address_balance.cpp
@@ -112,4 +112,37 @@ BOOST_AUTO_TEST_CASE(query_address__get_balance__block1a_address1_confirmed_bloc
     BOOST_REQUIRE_EQUAL(unconfirmed, 0u);
 }
 
+// duplicate instances (one tx archived twice, only one instance associated)
+
+BOOST_AUTO_TEST_CASE(query_address__get_balance__duplicate_instances__counted_once)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(!store.is_pooling());
+    BOOST_REQUIRE(query.initialize(test::genesis));
+    BOOST_REQUIRE(query.set(test::block1a, context{ 0, 1, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(1));
+    BOOST_REQUIRE(query.push_confirmed(1, false));
+    BOOST_REQUIRE(query.set(test::tx4));
+    BOOST_REQUIRE(query.set(test::block_spend_1a, context{ 0, 2, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(2));
+    BOOST_REQUIRE(query.push_confirmed(2, false));
+    BOOST_REQUIRE_EQUAL(query.to_duplicates(test::tx4.hash(false)).size(), 2u);
+
+    // block1a output 0 is spent by tx4, whose 0x08 output to the address is unspent.
+    uint64_t confirmed{};
+    uint64_t unconfirmed{};
+    const std::atomic_bool cancel{};
+    BOOST_REQUIRE_EQUAL(query.get_balance(cancel, confirmed, unconfirmed, test::block1a_address0, true), error::success);
+    BOOST_REQUIRE_EQUAL(confirmed, 0x08u);
+    BOOST_REQUIRE_EQUAL(unconfirmed, 0u);
+
+    uint64_t balance{};
+    BOOST_REQUIRE_EQUAL(query.get_confirmed_balance(cancel, balance, test::block1a_address0, true), error::success);
+    BOOST_REQUIRE_EQUAL(balance, 0x08u);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/test/query/address/address_history.cpp b/test/query/address/address_history.cpp
index 0facaf0cb..3149d9ae6 100644
--- a/test/query/address/address_history.cpp
+++ b/test/query/address/address_history.cpp
@@ -569,4 +569,82 @@ BOOST_AUTO_TEST_CASE(query_address__get_spenders_history__confirmed__expected)
     BOOST_CHECK_EQUAL(histories.at(3).tx.hash(), test::tx4.hash(false));
 }
 
+// duplicate instances (one tx archived twice, only one instance associated)
+
+BOOST_AUTO_TEST_CASE(query_address__get_tx_history__duplicate_instances__same_entry)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(!store.is_pooling());
+    BOOST_REQUIRE(query.initialize(test::genesis));
+    BOOST_REQUIRE(query.set(test::block1a, context{ 0, 1, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(1));
+    BOOST_REQUIRE(query.push_confirmed(1, false));
+    BOOST_REQUIRE(query.set(test::tx4));
+    const auto loose = query.to_tx(test::tx4.hash(false));
+    BOOST_REQUIRE(query.set(test::block_spend_1a, context{ 0, 2, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(2));
+    BOOST_REQUIRE(query.push_confirmed(2, false));
+    const auto stored = query.get_position_tx(query.to_header(test::block_spend_1a.hash()), 0);
+    BOOST_REQUIRE(stored != loose);
+
+    const auto expected = query.get_tx_history(stored);
+    BOOST_REQUIRE(expected.valid());
+    BOOST_REQUIRE(expected.confirmed());
+    BOOST_REQUIRE_EQUAL(expected.tx.height(), 2u);
+    BOOST_REQUIRE_EQUAL(expected.position, 0u);
+
+    const auto duplicate = query.get_tx_history(loose);
+    BOOST_REQUIRE(!duplicate.fault());
+    BOOST_REQUIRE(duplicate.valid());
+    BOOST_REQUIRE(duplicate == expected);
+    BOOST_REQUIRE_EQUAL(duplicate.tx.height(), 2u);
+    BOOST_REQUIRE_EQUAL(duplicate.position, 0u);
+
+    const auto confirmed = query.get_tx_confirmed_history(loose);
+    BOOST_REQUIRE(!confirmed.fault());
+    BOOST_REQUIRE(confirmed == expected);
+}
+
+BOOST_AUTO_TEST_CASE(query_address__get_history__duplicate_instances__deduplicated)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(!store.is_pooling());
+    BOOST_REQUIRE(query.initialize(test::genesis));
+    BOOST_REQUIRE(query.set(test::block1a, context{ 0, 1, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(1));
+    BOOST_REQUIRE(query.push_confirmed(1, false));
+    BOOST_REQUIRE(query.set(test::tx4));
+    BOOST_REQUIRE(query.set(test::block_spend_1a, context{ 0, 2, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(2));
+    BOOST_REQUIRE(query.push_confirmed(2, false));
+    BOOST_REQUIRE_EQUAL(query.to_duplicates(test::tx4.hash(false)).size(), 2u);
+
+    histories out{};
+    height_link cursor{};
+    const std::atomic_bool cancel{};
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, max_size_t, true), error::success);
+
+    // block1a coinbase (funds address0) and tx4 (spends it, pays address0), once each.
+    BOOST_REQUIRE_EQUAL(out.size(), 2u);
+    BOOST_REQUIRE_EQUAL(out.at(0).tx.hash(), test::block1a.transactions_ptr()->at(0)->hash(false));
+    BOOST_REQUIRE_EQUAL(out.at(0).tx.height(), 1u);
+    BOOST_REQUIRE_EQUAL(out.at(1).tx.hash(), test::tx4.hash(false));
+    BOOST_REQUIRE_EQUAL(out.at(1).tx.height(), 2u);
+    BOOST_REQUIRE_EQUAL(out.at(1).position, 0u);
+
+    histories confirmed{};
+    height_link confirmed_cursor{};
+    BOOST_REQUIRE_EQUAL(query.get_confirmed_history(cancel, confirmed_cursor, confirmed, test::block1a_address0, max_size_t, true), error::success);
+    BOOST_REQUIRE_EQUAL(confirmed.size(), 2u);
+    BOOST_REQUIRE_EQUAL(confirmed.at(1).tx.hash(), test::tx4.hash(false));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/test/query/address/address_unspent.cpp b/test/query/address/address_unspent.cpp
index 3f853bae4..f58011337 100644
--- a/test/query/address/address_unspent.cpp
+++ b/test/query/address/address_unspent.cpp
@@ -171,4 +171,45 @@ BOOST_AUTO_TEST_CASE(query_address__get_unspent__turbo_genesis__expected)
     BOOST_CHECK_EQUAL(out.at(5).out.point().hash(), test::block2b.transactions_ptr()->at(0)->hash(false));
 }
 
+// duplicate instances (one tx archived twice, only one instance associated)
+
+BOOST_AUTO_TEST_CASE(query_address__get_unspent__duplicate_instances__deduplicated)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(!store.is_pooling());
+    BOOST_REQUIRE(query.initialize(test::genesis));
+    BOOST_REQUIRE(query.set(test::block1a, context{ 0, 1, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(1));
+    BOOST_REQUIRE(query.push_confirmed(1, false));
+    BOOST_REQUIRE(query.set(test::tx4));
+    BOOST_REQUIRE(query.set(test::block_spend_1a, context{ 0, 2, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(2));
+    BOOST_REQUIRE(query.push_confirmed(2, false));
+    BOOST_REQUIRE_EQUAL(query.to_duplicates(test::tx4.hash(false)).size(), 2u);
+
+    // block1a output 0 is spent by tx4, whose 0x08 output to the address is unspent.
+    unspent_outputs out{};
+    const std::atomic_bool cancel{};
+    BOOST_REQUIRE_EQUAL(query.get_unspent(cancel, out, test::block1a_address0, true), error::success);
+    BOOST_REQUIRE_EQUAL(out.size(), 1u);
+    BOOST_REQUIRE_EQUAL(out.at(0).out.point().hash(), test::tx4.hash(false));
+    BOOST_REQUIRE_EQUAL(out.at(0).out.point().index(), 0u);
+    BOOST_REQUIRE_EQUAL(out.at(0).out.value(), 0x08u);
+    BOOST_REQUIRE_EQUAL(out.at(0).height, 2u);
+    BOOST_REQUIRE_EQUAL(out.at(0).position, 0u);
+
+    unspent_outputs confirmed{};
+    BOOST_REQUIRE_EQUAL(query.get_confirmed_unspent(cancel, confirmed, test::block1a_address0, true), error::success);
+    BOOST_REQUIRE_EQUAL(confirmed.size(), 1u);
+    BOOST_REQUIRE_EQUAL(confirmed.at(0).out.point().hash(), test::tx4.hash(false));
+
+    unspent_outputs unconfirmed{};
+    BOOST_REQUIRE_EQUAL(query.get_unconfirmed_unspent(cancel, unconfirmed, test::block1a_address0, true), error::success);
+    BOOST_REQUIRE(unconfirmed.empty());
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/test/query/consensus/consensus_strong.cpp b/test/query/consensus/consensus_strong.cpp
index 652992d55..2d40268df 100644
--- a/test/query/consensus/consensus_strong.cpp
+++ b/test/query/consensus/consensus_strong.cpp
@@ -211,4 +211,69 @@ BOOST_AUTO_TEST_CASE(query_consensus__set_strong__set_unstrong__expected)
     BOOST_REQUIRE(!query.is_confirmed_output(query.to_output(2, 0)));
 }
 
+// duplicate instances (one tx archived twice, only one instance associated)
+
+BOOST_AUTO_TEST_CASE(query_consensus__duplicate_instances__navigation__expected)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+
+    class accessor
+      : public test::query_accessor
+    {
+    public:
+        using test::query_accessor::query_accessor;
+        using test::query_accessor::to_block;
+    };
+
+    accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(!store.is_pooling());
+    BOOST_REQUIRE(query.initialize(test::genesis));
+    BOOST_REQUIRE(query.set(test::block1a, context{ 0, 1, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(1));
+    BOOST_REQUIRE(query.push_confirmed(1, false));
+
+    BOOST_REQUIRE(query.set(test::tx4));
+    const auto loose = query.to_tx(test::tx4.hash(false));
+    BOOST_REQUIRE(!loose.is_terminal());
+
+    BOOST_REQUIRE(query.set(test::block_spend_1a, context{ 0, 2, 0 }, {}, false, false));
+    BOOST_REQUIRE(query.set_strong(2));
+    BOOST_REQUIRE(query.push_confirmed(2, false));
+
+    const auto block = query.to_header(test::block_spend_1a.hash());
+    const auto stored = query.get_position_tx(block, 0);
+    BOOST_REQUIRE(!stored.is_terminal());
+    BOOST_REQUIRE(stored != loose);
+    BOOST_REQUIRE_EQUAL(query.get_tx_key(stored), test::tx4.hash(false));
+    BOOST_REQUIRE_EQUAL(query.to_duplicates(test::tx4.hash(false)).size(), 2u);
+
+    // The association is instance-exact.
+    BOOST_REQUIRE(query.to_block(loose).is_terminal());
+    BOOST_REQUIRE_EQUAL(query.to_block(stored), block);
+
+    // Strong resolution is by identity, from any instance.
+    BOOST_REQUIRE_EQUAL(query.find_strong(loose), block);
+    BOOST_REQUIRE_EQUAL(query.find_strong(stored), block);
+    BOOST_REQUIRE_EQUAL(query.find_strong_tx(loose), stored);
+    BOOST_REQUIRE_EQUAL(query.find_strong_tx(stored), stored);
+    BOOST_REQUIRE(query.is_confirmed_tx(loose));
+    BOOST_REQUIRE(query.is_confirmed_tx(stored));
+
+    // Confirmed properties are of the identity, from any instance.
+    size_t height{};
+    BOOST_REQUIRE(query.get_tx_height(height, loose));
+    BOOST_REQUIRE_EQUAL(height, 2u);
+    BOOST_REQUIRE(query.get_tx_height(height, stored));
+    BOOST_REQUIRE_EQUAL(height, 2u);
+
+    size_t position{};
+    BOOST_REQUIRE(query.get_tx_position(position, stored));
+    BOOST_REQUIRE_EQUAL(position, 0u);
+    BOOST_REQUIRE(query.get_tx_position(position, loose));
+    BOOST_REQUIRE_EQUAL(position, 0u);
+}
+
 BOOST_AUTO_TEST_SUITE_END()