diff --git a/modules/purchase_trade/__init__.py b/modules/purchase_trade/__init__.py
index 3ef10bb..499ce9d 100755
--- a/modules/purchase_trade/__init__.py
+++ b/modules/purchase_trade/__init__.py
@@ -30,6 +30,7 @@ from . import (
     valuation,
     dimension,
     weight_report,
+    backtoback,
     service,
 )
 
@@ -165,6 +166,7 @@ def register():
         purchase.DocTemplate,
         purchase.DocTypeTemplate,
         purchase.PurchaseStrategy,
+        backtoback.Backtoback,
         dimension.AnalyticDimension,
         dimension.AnalyticDimensionValue,
         dimension.AnalyticDimensionAssignment,
@@ -210,6 +212,7 @@ def register():
         sale.ContractDocumentType,
         sale.SaleStrategy,
         sale.OpenPosition,
+        sale.Backtoback,
         module='sale', type_='model')
     Pool.register(
         lot.LotShipping,
diff --git a/modules/purchase_trade/backtoback.py b/modules/purchase_trade/backtoback.py
new file mode 100644
index 0000000..baf25d3
--- /dev/null
+++ b/modules/purchase_trade/backtoback.py
@@ -0,0 +1,22 @@
+from trytond.model import fields
+from trytond.pool import Pool, PoolMeta
+from trytond.pyson import Bool, Eval, Id
+from trytond.model import (ModelSQL, ModelView)
+from trytond.tools import is_full_text, lstrip_wildcard
+from trytond.transaction import Transaction, inactive_records
+from decimal import getcontext, Decimal, ROUND_HALF_UP
+from sql.aggregate import Count, Max, Min, Sum, Avg, BoolOr
+from sql.conditionals import Case
+from sql import Column, Literal
+from sql.functions import CurrentTimestamp, DateTrunc
+from trytond.wizard import Button, StateTransition, StateView, Wizard
+import datetime
+import logging
+
+class Backtoback(ModelSQL, ModelView):
+    'Back To Back'
+    __name__ = 'back.to.back'
+
+    reference = fields.Char("Reference")
+    purchase = fields.One2Many('purchase.purchase', "Purchase")
+    
\ No newline at end of file
diff --git a/modules/purchase_trade/backtoback.xml b/modules/purchase_trade/backtoback.xml
new file mode 100644
index 0000000..0facbc1
--- /dev/null
+++ b/modules/purchase_trade/backtoback.xml
@@ -0,0 +1,54 @@
+<tryton>
+    <data>
+        <record model="ir.ui.icon" id="btb_icon">
+            <field name="name">tradon-btb</field>
+            <field name="path">icons/tradon-btb.svg</field>
+        </record>
+
+        <record model="ir.ui.view" id="btb_view_form">
+            <field name="model">back.to.back</field>
+            <field name="type">form</field>
+            <field name="name">btb_form</field>
+        </record>
+
+        <record model="ir.ui.view" id="purchase_btb_view_form">
+            <field name="model">purchase.purchase</field>
+            <field name="type">form</field>
+            <field name="name">purchase_btb_form</field>
+        </record>
+
+        <record model="ir.ui.view" id="btb_view_list">
+            <field name="model">back.to.back</field>
+            <field name="type">tree</field>
+            <field name="name">btb_tree</field>
+        </record>
+        
+        <record model="ir.action.act_window" id="act_btb_form">
+            <field name="name">Back to back</field>
+            <field name="res_model">back.to.back</field>
+        </record>
+        <record model="ir.action.act_window.view" id="act_btb_form_view1">
+            <field name="sequence" eval="10"/>
+            <field name="view" ref="btb_view_list"/>
+            <field name="act_window" ref="act_btb_form"/>
+        </record>
+        <record model="ir.action.act_window.view" id="act_btb_form_view2">
+            <field name="sequence" eval="20"/>
+            <field name="view" ref="btb_view_form"/>
+            <field name="act_window" ref="act_btb_form"/>
+        </record>
+
+        <menuitem
+            name="Back to back"
+            sequence="99"
+            id="menu_btb_main"
+            icon="tradon-btb" />
+        <menuitem
+            name="Back to back"
+            action="act_btb_form"
+            parent="menu_btb_main"
+            sequence="10"
+            id="menu_btb" />
+        
+    </data>
+</tryton>
\ No newline at end of file
diff --git a/modules/purchase_trade/icons/tradon-btb.svg b/modules/purchase_trade/icons/tradon-btb.svg
new file mode 100644
index 0000000..779a456
--- /dev/null
+++ b/modules/purchase_trade/icons/tradon-btb.svg
@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+    <path d="M0 0h24v24H0z" fill="none"/>
+
+    <!-- Barre centrale (contrat / position) -->
+    <rect x="11" y="4" width="2" height="16" fill="#267F82"/>
+
+    <!-- Flèche gauche (achat) -->
+    <path d="M9 7 L5 12 L9 17 L9 14 L11 14 L11 10 L9 10 Z"
+          fill="#267F82"/>
+
+    <!-- Flèche droite (vente) -->
+    <path d="M15 7 L19 12 L15 17 L15 14 L13 14 L13 10 L15 10 Z"
+          fill="#267F82"/>
+</svg>
diff --git a/modules/purchase_trade/sale.py b/modules/purchase_trade/sale.py
index 3b021cb..0537520 100755
--- a/modules/purchase_trade/sale.py
+++ b/modules/purchase_trade/sale.py
@@ -45,6 +45,12 @@ class FeeLots(metaclass=PoolMeta):
 
     sale_line = fields.Many2One('sale.line',"Line")
 
+class Backtoback(metaclass=PoolMeta):
+    'Back To Back'
+    __name__ = 'back.to.back'
+
+    sale = fields.One2Many('sale.sale', "Sale")
+
 class OpenPosition(metaclass=PoolMeta):
     "Open position"
     __name__ = 'open.position'
diff --git a/modules/purchase_trade/sale.xml b/modules/purchase_trade/sale.xml
index f598208..a164d93 100755
--- a/modules/purchase_trade/sale.xml
+++ b/modules/purchase_trade/sale.xml
@@ -52,5 +52,11 @@ this repository contains the full copyright notices and license terms. -->
             <field name="model">sale.sale,-1</field>
             <field name="action" ref="act_sale_allocations_wizard"/>
         </record>
+
+        <record model="ir.ui.view" id="sale_btb_view_form">
+            <field name="model">sale.sale</field>
+            <field name="type">form</field>
+            <field name="name">sale_btb_form</field>
+        </record>
     </data>
 </tryton>
\ No newline at end of file
diff --git a/modules/purchase_trade/tryton.cfg b/modules/purchase_trade/tryton.cfg
index 16a1f53..6a141bf 100755
--- a/modules/purchase_trade/tryton.cfg
+++ b/modules/purchase_trade/tryton.cfg
@@ -31,4 +31,5 @@ xml:
     derivative.xml
     valuation.xml
     weight_report.xml
-    dimension.xml
\ No newline at end of file
+    dimension.xml
+    backtoback.xml
\ No newline at end of file
diff --git a/modules/purchase_trade/view/btb_form.xml b/modules/purchase_trade/view/btb_form.xml
new file mode 100644
index 0000000..c84b09e
--- /dev/null
+++ b/modules/purchase_trade/view/btb_form.xml
@@ -0,0 +1,10 @@
+<form>
+    <label name="reference"/>
+    <field name="reference"/>
+    <newline/>
+    <label name="purchase"/>
+    <field name="purchase" mode="form" view_ids="purchase_trade.purchase_btb_view_form"/>
+    <newline/>
+    <label name="sale"/>
+    <field name="sale" mode="form" view_ids="purchase_trade.sale_btb_view_form"/>
+</form>
\ No newline at end of file
diff --git a/modules/purchase_trade/view/btb_tree.xml b/modules/purchase_trade/view/btb_tree.xml
new file mode 100644
index 0000000..160e282
--- /dev/null
+++ b/modules/purchase_trade/view/btb_tree.xml
@@ -0,0 +1,5 @@
+<tree>
+    <field name="reference"/>
+    <field name="purchase"/>
+    <field name="sale"/>
+</tree>
\ No newline at end of file
diff --git a/modules/purchase_trade/view/purchase_btb_form.xml b/modules/purchase_trade/view/purchase_btb_form.xml
new file mode 100644
index 0000000..286f506
--- /dev/null
+++ b/modules/purchase_trade/view/purchase_btb_form.xml
@@ -0,0 +1,70 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<form col="6">
+    <group col="4" colspan="4" id="hd" yfill="1">
+        <label name="party"/>
+        <field name="party"/>
+        <label name="number"/>
+        <field name="number"/>
+        <newline/>
+        <label name="reference"/>
+        <field name="reference"/>
+        <label name="purchase_date"/>
+        <field name="purchase_date"/>
+        <newline/>
+        <label name="payment_term"/>
+        <field name="payment_term"/>
+        <label name="currency"/>
+        <field name="currency"/>
+        <newline/>
+        <label name="certif"/>
+        <field name="certif"/>
+    </group>
+    <group col="2" colspan="2" id="hd" yfill="1">
+        <field name="viewer" widget="html_viewer" height="300" width="600"/>
+    </group>
+    <notebook colspan="6">
+        <page string="Purchase" id="purchase">
+            <field name="lines" colspan="4"
+                view_ids="purchase.purchase_line_view_tree_sequence"/>
+            <notebook colspan="6">
+                <page string="State" id="state">
+                    <group col="2" colspan="2" id="states" yfill="1">
+                        <label name="invoice_state"/>
+                        <field name="invoice_state"/>
+                        <label name="shipment_state"/>
+                        <field name="shipment_state"/>
+                        <label name="state"/>
+                        <field name="state"/>
+                    </group>
+                    <group col="2" colspan="2" id="amount" yfill="1">
+                        <label name="untaxed_amount" xalign="1.0" xexpand="1"/>
+                        <field name="untaxed_amount" xalign="1.0" xexpand="0"/>
+                        <label name="tax_amount" xalign="1.0" xexpand="1"/>
+                        <field name="tax_amount" xalign="1.0" xexpand="0"/>
+                        <label name="total_amount" xalign="1.0" xexpand="1"/>
+                        <field name="total_amount" xalign="1.0" xexpand="0"/>
+                    </group>
+                </page>
+            </notebook>
+        </page>
+    </notebook>
+    <group id="links" col="-1" colspan="3">
+        <link icon="tryton-shipment-in" name="purchase.act_shipment_form"/>
+        <link icon="tryton-account" name="purchase.act_invoice_form"/>
+        <!-- <link icon="tryton-shipment-out" name="purchase.act_return_form"/> -->
+    </group>
+    <group col="-1" colspan="3" id="buttons">
+        <button name="cancel" icon="tryton-cancel"/>
+        <button name="draft"/>
+        <button name="modify_header" icon="tryton-launch"/>
+        <button name="quote" icon="tryton-forward"/>
+        <button name="handle_invoice_exception" icon="tryton-forward"/>
+        <button name="handle_shipment_exception" icon="tryton-forward"/>
+        <button name="confirm" icon="tryton-ok"/>
+        <button name="process"/>
+        <button name="manual_invoice" icon="tryton-forward"/>
+    </group>
+    <field name="party_lang" invisible="1" colspan="6"/>
+</form>
diff --git a/modules/purchase_trade/view/sale_btb_form.xml b/modules/purchase_trade/view/sale_btb_form.xml
new file mode 100644
index 0000000..fc9b3fa
--- /dev/null
+++ b/modules/purchase_trade/view/sale_btb_form.xml
@@ -0,0 +1,73 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<form col="6">
+    <group col="4" colspan="4" id="hd" yfill="1">
+        <label name="party"/>
+        <field name="party"/>
+        <label name="number"/>
+        <field name="number"/>
+        <!-- <label name="contact"/>
+        <field name="contact"/> -->
+        <newline/>
+        <label name="reference"/>
+        <field name="reference"/>
+        <label name="sale_date"/>
+        <field name="sale_date"/>
+        <newline/>
+        <label name="payment_term"/>
+        <field name="payment_term"/>
+        <label name="currency"/>
+        <field name="currency"/>
+        <newline/>
+        <label name="certif"/>
+        <field name="certif"/>
+    </group>
+    <group col="2" colspan="2" id="hd" yfill="1">
+        <field name="viewer" widget="html_viewer" height="300" width="600"/>
+    </group>
+    <notebook colspan="6">
+        <page string="Sale" id="sale">
+            <field name="lines" colspan="4"
+                view_ids="sale.sale_line_view_tree_sequence"/>
+            <notebook colspan="6">
+                <page string="State" id="state">
+                    <group col="2" colspan="2" id="states" yfill="1">
+                        <label name="invoice_state"/>
+                        <field name="invoice_state"/>
+                        <label name="shipment_state"/>
+                        <field name="shipment_state"/>
+                        <label name="state"/>
+                        <field name="state"/>
+                    </group>
+                    <group col="2" colspan="2" id="amount" yfill="1">
+                        <label name="untaxed_amount" xalign="1.0" xexpand="1"/>
+                        <field name="untaxed_amount" xalign="1.0" xexpand="0"/>
+                        <label name="tax_amount" xalign="1.0" xexpand="1"/>
+                        <field name="tax_amount" xalign="1.0" xexpand="0"/>
+                        <label name="total_amount" xalign="1.0" xexpand="1"/>
+                        <field name="total_amount" xalign="1.0" xexpand="0"/>
+                    </group>
+                </page>
+            </notebook>
+        </page>
+    </notebook>
+    <group id="links" col="-1" colspan="3">
+        <link icon="tryton-shipment-out" name="sale.act_shipment_form"/>
+        <link icon="tryton-account" name="sale.act_invoice_form"/>
+        <link icon="tryton-shipment-in" name="sale.act_return_form"/>
+    </group>
+    <group col="-1" colspan="3" id="buttons">
+        <button name="cancel" icon="tryton-cancel"/>
+        <button name="modify_header" icon="tryton-launch"/>
+        <button name="draft"/>
+        <button name="quote" icon="tryton-forward"/>
+        <button name="handle_invoice_exception" icon="tryton-forward"/>
+        <button name="handle_shipment_exception" icon="tryton-forward"/>
+        <button name="confirm" icon="tryton-forward"/>
+        <button name="process"/>
+        <button name="manual_invoice" icon="tryton-forward"/>
+        <button name="manual_shipment" icon="tryton-forward"/>
+    </group>
+    <field name="party_lang" invisible="1" colspan="6"/>
+</form>