Some say it tastes better if leek or mustard isn't added while stirring but small quantity of them are placed on the top after stirring, similar to the manner of adding leek or wasabi (Japanese horseradish) when eating soba (buckwheat noodles).
ネギやからしを途中で加えずに、蕎麦のネギやわさびと同様に最後に少しだけ載せた方がおいしいという人もいる。