Why she chose your sofa in the first place
Scratching is not naughtiness; it maintains your cat's claws, stretches her shoulders and back, and leaves a visible and scented mark in a social area of the home. Your sofa scores highly on all counts — it stands in the room where everyone gathers, its fabric gives satisfying resistance, and its arms are at a perfect height for a full upright stretch. She picked the best scratching site in the house by feline standards, which is why simply telling her off never holds.
Punishment also misses the timing problem. She scratches when she wakes, after play, and when she greets you, often when you are not beside the sofa to intervene. The durable fix is to change which object delivers the best scratch in that exact spot, not to police her around the clock.
Put the alternative in the exact place she scratches
Position a tall, heavy, completely stable post directly in front of the sofa arm or corner she uses, close enough that she encounters it first. Wobble is the most common reason cats reject a new post: if it rocks when she leans in, she returns to the solid sofa. Match her preference too — a cat who scratches the vertical arm usually wants a vertical sisal post tall enough for a full stretch, while a cat who rakes the seat cushion often prefers a horizontal or sloped surface.
Draw her to it with play around its base, a favourite scent rubbed into the material, and immediate praise or a small treat when she sinks her claws in. For the first week or two, reward every single use generously; habits form through repetition, and you are asking her to abandon a site she loves. Only once she is choosing the post reliably should you move it gradually, a short distance at a time, to where you would prefer it to live.
Make the sofa less satisfying while she learns
Cover the targeted area with a tightly fitted throw, a smooth blanket, or a purpose-made guard so her claws slip instead of shredding satisfyingly. Loose covers that bunch up invite play, so secure them well. Keep the cover on during the highest-risk moments — after naps and when you come home — and remove it only when you can supervise and redirect.
Keep her nails trimmed so accidental catches do less damage, and agree as a household that the response is always a calm transfer to the post.
Read the pattern behind heavy scratching
A cat whose scratching suddenly escalates may be marking more because she feels insecure — a new pet, building work, a house move, or tension with another cat in the home can all increase territorial scratching. In that case, add scratching options in several rooms rather than fighting over the single sofa site, and give her quiet resting places where she is not disturbed.
Scratching paired with restlessness, over-grooming, or appetite change is worth raising with your veterinarian, since discomfort and stress-related conditions can sit behind a behaviour change. For the ordinary sofa case, though, expect steady improvement over a few weeks as the post becomes her established first choice, and keep rewarding it long after the sofa is safe — habits that stop being acknowledged sometimes quietly return.
Share the small jobs that keep the habit in place
Post training works when nail trims happen on schedule, play sessions burn off the energy that fuels extra marking, and everyone redirects her identically. Dividing those jobs stops them depending on whoever happens to notice. In KinsLe Care Teams you can assign nail-care and daily play duties for your cat to different family members, with each completed task timestamped, so her good scratching habit gets steady support from the whole household.