It is mentioned in the Rakugo (comic storytelling) classic 'Toki soba' but, nowadays, Shippoku soba is frequently not available at soba restaurants in the Kanto region.
古典落語『時そば』の中にも「しっぽく」が出てくるが、現在の関東地方の蕎麦屋には無いことが多い。