diff --git a/CLAUDE.md b/CLAUDE.md
index 672e5a9..0d9836b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -124,6 +124,7 @@ type PricelistItem struct {
 ### ВАЖНО:
 - Категория НЕ виртуальное поле - она сохраняется в БД при создании прайслиста
 - JOIN с таблицей `lot` нужен только для `lot_description`, категория уже есть в `qt_pricelist_items`
+- Никогда не получать категорию из имени элемента (lot name/названия). Всегда использовать категорию из `PricelistItem` (поле `lot_category` / JSON `category`).
 
 ## Notes
 - Главная страница должна вести на `/admin/pricing`.
diff --git a/MEMORY.md b/MEMORY.md
new file mode 100644
index 0000000..d7f42dd
--- /dev/null
+++ b/MEMORY.md
@@ -0,0 +1,31 @@
+# PriceForge Memory
+
+## LOT Page Refactoring (2026-02-10)
+
+**What was done:**
+- Created new dedicated `/lot` page with two tabs:
+  1. **LOT tab**: Component/article management (table with search, sort, create LOT)
+  2. **Сопоставления tab**: partnumber ↔ LOT mappings management
+
+- Removed LOT tab from "Администратор цен" (Pricing Admin)
+- Removed "Сопоставление partnumber → LOT" section from Warehouse tab
+- Updated main menu navigation:
+  - LOT link → /lot (new page)
+  - Администратор цен → /admin/pricing (Estimate, Склад, Конкуренты)
+  - Настройки (unchanged)
+
+**Files changed:**
+- `web/templates/lot.html` (NEW) - Complete page with LOT and stock mappings tabs
+- `web/templates/base.html` - Updated menu to link LOT to /lot
+- `web/templates/admin_pricing.html` - Removed LOT tab, changed default to Estimate
+- `internal/handlers/web.go` - Added lot.html to template list, added Lot() handler
+- `cmd/pfs/main.go` - Added /lot route
+
+**Technical notes:**
+- lot.html uses same API endpoints as admin_pricing for data loading
+- Stock mappings functions copied from admin_pricing.html but adapted for new page
+- Default tab for Pricing Admin is now 'estimate' instead of 'lots'
+
+## Data Rules (2026-02-18)
+
+- Never derive category from item name (lot name). Always use category from `PricelistItem` (`lot_category` / JSON `category`).
diff --git a/internal/models/category.go b/internal/models/category.go
index ca970c4..a4a28f3 100644
--- a/internal/models/category.go
+++ b/internal/models/category.go
@@ -9,6 +9,9 @@ type Category struct {
 	IsRequired   bool   `gorm:"default:false" json:"is_required"`
 }
 
+// DefaultLotCategoryCode is used when a lot has no category in DB.
+const DefaultLotCategoryCode = "PART_"
+
 func (Category) TableName() string {
 	return "qt_categories"
 }
diff --git a/internal/services/component.go b/internal/services/component.go
index 8eed3ac..ab2e07f 100644
--- a/internal/services/component.go
+++ b/internal/services/component.go
@@ -183,13 +183,18 @@ func (s *ComponentService) ImportFromLot() (int, error) {
 
 	imported := 0
 	for _, lot := range lots {
-		// Use lot_category from database if available, otherwise parse from lot_name
+		// Use lot_category from database only (never derive from lot_name).
+		// If empty, assign default and persist to DB.
 		var category string
 		if lot.LotCategory != nil && *lot.LotCategory != "" {
 			category = strings.ToUpper(*lot.LotCategory)
 		} else {
-			category, _ = ParsePartNumber(lot.LotName)
-			category = strings.ToUpper(category)
+			category = models.DefaultLotCategoryCode
+			if s.componentRepo != nil {
+				_ = s.componentRepo.DB().Model(&models.Lot{}).
+					Where("lot_name = ?", lot.LotName).
+					Update("lot_category", category).Error
+			}
 		}
 
 		_, model := ParsePartNumber(lot.LotName)
@@ -200,13 +205,15 @@ func (s *ComponentService) ImportFromLot() (int, error) {
 			Specs:   make(models.Specs),
 		}
 
-		if catID, ok := categoryMap[category]; ok {
-			metadata.CategoryID = &catID
-		} else {
-			// Create new category if it doesn't exist
-			newCat, err := s.categoryRepo.CreateIfNotExists(category)
-			if err == nil && newCat != nil {
-				metadata.CategoryID = &newCat.ID
+		if category != "" {
+			if catID, ok := categoryMap[category]; ok {
+				metadata.CategoryID = &catID
+			} else {
+				// Create new category if it doesn't exist
+				newCat, err := s.categoryRepo.CreateIfNotExists(category)
+				if err == nil && newCat != nil {
+					metadata.CategoryID = &newCat.ID
+				}
 			}
 		}
 
diff --git a/internal/services/pricelist/service.go b/internal/services/pricelist/service.go
index 3e932f2..c468073 100644
--- a/internal/services/pricelist/service.go
+++ b/internal/services/pricelist/service.go
@@ -189,14 +189,27 @@ func (s *Service) CreateForSourceWithProgress(createdBy, source string, sourceIt
 		}
 
 		categoryMap := make(map[string]*string)
+		missingCategoryLots := make([]string, 0)
+		defaultCategory := models.DefaultLotCategoryCode
 		if len(lotNames) > 0 {
 			var lots []models.Lot
 			if err := s.db.Where("lot_name IN ?", lotNames).Find(&lots).Error; err == nil {
 				for _, lot := range lots {
+					if lot.LotCategory == nil || strings.TrimSpace(*lot.LotCategory) == "" {
+						categoryMap[lot.LotName] = &defaultCategory
+						missingCategoryLots = append(missingCategoryLots, lot.LotName)
+						continue
+					}
 					categoryMap[lot.LotName] = lot.LotCategory
 				}
 			}
 		}
+		if len(missingCategoryLots) > 0 {
+			ensureCategoryExists(s.db, defaultCategory)
+			_ = s.db.Model(&models.Lot{}).
+				Where("lot_name IN ?", missingCategoryLots).
+				Update("lot_category", defaultCategory).Error
+		}
 
 		items = make([]models.PricelistItem, 0, len(sourceItems))
 		for _, srcItem := range sourceItems {
@@ -204,11 +217,9 @@ func (s *Service) CreateForSourceWithProgress(createdBy, source string, sourceIt
 			if lotName == "" || srcItem.Price <= 0 {
 				continue
 			}
-			category := strings.TrimSpace(srcItem.Category)
-			if category == "" {
-				if catPtr, ok := categoryMap[lotName]; ok && catPtr != nil {
-					category = *catPtr
-				}
+			var category string
+			if catPtr, ok := categoryMap[lotName]; ok && catPtr != nil {
+				category = *catPtr
 			}
 			items = append(items, models.PricelistItem{
 				PricelistID: pricelist.ID,
@@ -241,14 +252,27 @@ func (s *Service) CreateForSourceWithProgress(createdBy, source string, sourceIt
 		}
 
 		categoryMap := make(map[string]*string)
+		missingCategoryLots := make([]string, 0)
+		defaultCategory := models.DefaultLotCategoryCode
 		if len(lotNames) > 0 {
 			var lots []models.Lot
 			if err := s.db.Where("lot_name IN ?", lotNames).Find(&lots).Error; err == nil {
 				for _, lot := range lots {
+					if lot.LotCategory == nil || strings.TrimSpace(*lot.LotCategory) == "" {
+						categoryMap[lot.LotName] = &defaultCategory
+						missingCategoryLots = append(missingCategoryLots, lot.LotName)
+						continue
+					}
 					categoryMap[lot.LotName] = lot.LotCategory
 				}
 			}
 		}
+		if len(missingCategoryLots) > 0 {
+			ensureCategoryExists(s.db, defaultCategory)
+			_ = s.db.Model(&models.Lot{}).
+				Where("lot_name IN ?", missingCategoryLots).
+				Update("lot_category", defaultCategory).Error
+		}
 
 		// Create pricelist items with all price settings
 		items = make([]models.PricelistItem, 0, len(metadata))
@@ -295,6 +319,23 @@ func (s *Service) CreateForSourceWithProgress(createdBy, source string, sourceIt
 	return pricelist, nil
 }
 
+func ensureCategoryExists(db *gorm.DB, code string) {
+	var count int64
+	if err := db.Model(&models.Category{}).Where("code = ?", code).Count(&count).Error; err != nil || count > 0 {
+		return
+	}
+	var maxOrder int
+	if err := db.Model(&models.Category{}).Select("COALESCE(MAX(display_order), 0)").Scan(&maxOrder).Error; err != nil {
+		return
+	}
+	_ = db.Create(&models.Category{
+		Code:         code,
+		Name:         code,
+		NameRu:       code,
+		DisplayOrder: maxOrder + 1,
+	}).Error
+}
+
 func isVersionConflictError(err error) bool {
 	if errors.Is(err, gorm.ErrDuplicatedKey) {
 		return true
diff --git a/internal/warehouse/snapshot.go b/internal/warehouse/snapshot.go
index 9e906c7..56a51c2 100644
--- a/internal/warehouse/snapshot.go
+++ b/internal/warehouse/snapshot.go
@@ -85,12 +85,43 @@ func ComputePricelistItemsFromStockLog(db *gorm.DB) ([]SnapshotItem, error) {
 				}
 			}
 		}
+		defaultCategory := models.DefaultLotCategoryCode
+		missingCategoryLots := make([]string, 0)
+		for i := range items {
+			if strings.TrimSpace(items[i].Category) == "" {
+				items[i].Category = defaultCategory
+				missingCategoryLots = append(missingCategoryLots, items[i].LotName)
+			}
+		}
+		if len(missingCategoryLots) > 0 {
+			ensureCategoryExists(db, defaultCategory)
+			_ = db.Model(&models.Lot{}).
+				Where("lot_name IN ?", missingCategoryLots).
+				Update("lot_category", defaultCategory).Error
+		}
 	}
 
 	sort.Slice(items, func(i, j int) bool { return items[i].LotName < items[j].LotName })
 	return items, nil
 }
 
+func ensureCategoryExists(db *gorm.DB, code string) {
+	var count int64
+	if err := db.Model(&models.Category{}).Where("code = ?", code).Count(&count).Error; err != nil || count > 0 {
+		return
+	}
+	var maxOrder int
+	if err := db.Model(&models.Category{}).Select("COALESCE(MAX(display_order), 0)").Scan(&maxOrder).Error; err != nil {
+		return
+	}
+	_ = db.Create(&models.Category{
+		Code:         code,
+		Name:         code,
+		NameRu:       code,
+		DisplayOrder: maxOrder + 1,
+	}).Error
+}
+
 // LoadLotMetrics returns stock qty and partnumbers for selected lots.
 // If latestOnly is true, qty/partnumbers from stock_log are calculated only for latest import date.
 func LoadLotMetrics(db *gorm.DB, lotNames []string, latestOnly bool) (map[string]float64, map[string][]string, error) {