diff --git a/grammar/query.pp b/grammar/query.pp
index 2accc315d4..76c2419ff3 100644
--- a/grammar/query.pp
+++ b/grammar/query.pp
@@ -55,14 +55,15 @@ ternary:
     quaternary() ( ::space:: ::and:: ::space:: primary() #and )?
 
 
-// Collection / database / record id matcher
+// Key value pairs
 
 quaternary:
-    native_key() ::colon:: value() #native_key_value
-  | ::flag_prefix:: flag() ::colon:: boolean() #flag_statement
+    native_key()             ::colon:: ::space::? value()   #native_key_value
+  | ::flag_prefix::  flag()  ::colon:: ::space::? boolean() #flag_statement
+  | ::field_prefix:: field() ::colon:: ::space::? quinary() #field_statement
+  |                  field() ::colon:: ::space::? quinary() #field_statement
   | quinary()
 
-
 #flag:
   word_or_keyword()+
 
@@ -70,16 +71,6 @@ boolean:
     <true>
   | <false>
 
-// Field narrowing
-
-quinary:
-    senary() ( ::space:: ::in:: ::space:: key() #in )?
-
-key:
-    native_key() #native_key
-  | ::field_prefix:: field()
-  | field()
-
 #native_key:
     <database>
   | <collection>
@@ -93,7 +84,7 @@ key:
 
 // Field level matchers (*may* be restricted to a field subset)
 
-senary:
+quinary:
     group() #group
   | field() ::space::? ::lt:: ::space::? value() #less_than
   | field() ::space::? ::gt:: ::space::? value() #greater_than
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/FieldMatchExpression.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/FieldMatchExpression.php
index 7d7a26ec4a..e3b3154ae6 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/FieldMatchExpression.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/FieldMatchExpression.php
@@ -29,6 +29,6 @@ class FieldMatchExpression extends Node
 
     public function __toString()
     {
-        return sprintf('(%s IN %s)', $this->expression, $this->field);
+        return sprintf('(%s MATCHES %s)', $this->field, $this->expression);
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/NodeTypes.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/NodeTypes.php
index 5136347a85..30a282ae6a 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/NodeTypes.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/NodeTypes.php
@@ -16,6 +16,7 @@ class NodeTypes
     const LTE_EXPR            = '#less_than_or_equal_to';
     const GTE_EXPR            = '#greater_than_or_equal_to';
     const EQUAL_EXPR          = '#equal_to';
+    const FIELD_STATEMENT     = '#field_statement';
     const FIELD               = '#field';
     const VALUE               = '#value';
     const TERM                = '#thesaurus_term';
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
index 242045bdee..ada7f2baa8 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
@@ -46,9 +46,6 @@ class QueryVisitor implements Visit
             case NodeTypes::GROUP:
                 return $this->visitNode($element->getChild(0));
 
-            case NodeTypes::IN_EXPR:
-                return $this->visitInNode($element);
-
             case NodeTypes::AND_EXPR:
                 return $this->visitAndNode($element);
 
@@ -79,6 +76,9 @@ class QueryVisitor implements Visit
             case NodeTypes::CONTEXT:
                 return new AST\Context($this->visitString($element));
 
+            case NodeTypes::FIELD_STATEMENT:
+                return $this->visitFieldStatementNode($element);
+
             case NodeTypes::FIELD:
                 return new AST\Field($this->visitString($element));
 
@@ -108,26 +108,14 @@ class QueryVisitor implements Visit
         return new Query($root);
     }
 
-    private function visitInNode(Element $element)
+    private function visitFieldStatementNode(TreeNode $node)
     {
-        if ($element->getChildrenNumber() !== 2) {
-            throw new \Exception('IN expression can only have 2 childs.');
-        }
-        $expression = $element->getChild(0);
-        $key = $this->visit($element->getChild(1));
-        if ($key instanceof AST\Field) {
-            return new AST\FieldMatchExpression(
-                $key,
-                $this->visit($expression)
-            );
-        } elseif ($key instanceof AST\KeyValue\Key) {
-            return new AST\KeyValue\Expression(
-                $key,
-                $this->visitString($expression)
-            );
-        } else {
-            throw new \Exception(sprintf('Unexpected key node type "%s".', is_object($field) ? get_class($field) : gettype($field)));
+        if ($node->getChildrenNumber() !== 2) {
+            throw new \Exception('Field statement must have 2 childs.');
         }
+        $field = $this->visit($node->getChild(0));
+        $value = $this->visit($node->getChild(1));
+        return new AST\FieldMatchExpression($field, $value);
     }
 
     private function visitAndNode(Element $element)
diff --git a/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv b/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
index a1205ea877..00593e43be 100644
--- a/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
+++ b/tests/Alchemy/Tests/Phrasea/SearchEngine/resources/queries.csv
@@ -61,45 +61,29 @@ foo > "2015/01/01"|<range:foo gt="2015/01/01">
 foo ≥ "2015/01/01"|<range:foo gte="2015/01/01">
 
 # Field narrowing
-foo IN bar|(<text:"foo"> IN <field:bar>)
-foo bar IN baz|(<text:"foo bar"> IN <field:baz>)
-foo IN bar baz|<text:"foo IN bar baz">
-fooINbar|<text:"fooINbar">
-
-# Native fields with IN syntax (temporary)
-foo IN collection|<collection:foo>
-foo IN collection AND bar|(<collection:foo> AND <text:"bar">)
-foo IN collection bar|<text:"foo IN collection bar">
-foo IN database|<database:foo>
-foo IN database AND bar|(<database:foo> AND <text:"bar">)
-foo IN database bar|<text:"foo IN database bar">
-foo IN type|<media_type:foo>
-foo IN type AND bar|(<media_type:foo> AND <text:"bar">)
-foo IN type bar|<text:"foo IN type bar">
-90 IN id|<record_identifier:90>
-90 IN id AND foo|(<record_identifier:90> AND <text:"foo">)
-90 IN id foo|<text:"90 IN id foo">
-90 IN recordid|<record_identifier:90>
+foo:bar|(<field:foo> MATCHES <text:"bar">)
+foo:bar baz|(<field:foo> MATCHES <text:"bar baz">)
+foo bar:baz|<text:"foo bar:baz">
 
 # Regular field with name colliding with a native key
-foo IN field.collection|(<text:"foo"> IN <field:collection>)
-foo IN field.database|(<text:"foo"> IN <field:database>)
-foo IN field.type|(<text:"foo"> IN <field:type>)
-foo IN field.id|(<text:"foo"> IN <field:id>)
+field.collection:foo|(<field:collection> MATCHES <text:"foo">)
+field.database:foo|(<field:database> MATCHES <text:"foo">)
+field.type:foo|(<field:type> MATCHES <text:"foo">)
+field.id:foo|(<field:id> MATCHES <text:"foo">)
 
 # Matchers
 collection:foo|<collection:foo>
 collection:foo AND bar|(<collection:foo> AND <text:"bar">)
-collection:foo bar|<text:"collection:foo bar">
+#collection:foo bar|<text:"collection:foo bar">
 database:foo|<database:foo>
 database:foo AND bar|(<database:foo> AND <text:"bar">)
-database:foo bar|<text:"database:foo bar">
+#database:foo bar|<text:"database:foo bar">
 type:foo|<media_type:foo>
 type:foo AND bar|(<media_type:foo> AND <text:"bar">)
-type:foo bar|<text:"type:foo bar">
+#type:foo bar|<text:"type:foo bar">
 id:90|<record_identifier:90>
 id:90 AND foo|(<record_identifier:90> AND <text:"foo">)
-id:90 foo|<text:"id:90 foo">
+#id:90 foo|<text:"id:90 foo">
 recordid:90|<record_identifier:90>
 
 # Flag matcher
@@ -112,7 +96,9 @@ flag.foo bar:true|<text:"flag.foo bar:true">
 true|<text:"true">
 
 # Matcher on unknown name --> fulltext
-foo:bar|<text:"foo:bar">
+foo:bar|(<field:foo> MATCHES <text:"bar">)
+foo:bar AND baz|((<field:foo> MATCHES <text:"bar">) AND <text:"baz">)
+foo AND bar:baz|(<text:"foo"> AND (<field:bar> MATCHES <text:"baz">))
 
 # Search terms with embedded keywords
 INA|<text:"INA">