Do restaurants in Japan provide knife and fork?

You can get collapsible cutlery; they are small enough to put into your pocket, in case the restaurant doesn’t have a set of western cutlery available for guests.

However, you might want to ask before using your own; I’m not a expert on Japanese etiquette to know how to do this politely.

I’ve been to Japan about 60 times. I’ve sometimes traveled with colleagues who struggle with chopsticks. Usually, they have had no difficulty: most restaurants have knives and forks. But I do recall one instance where somebody wound up eating lunch with a large kitchen spoon ツ.

However, while I don’t find chopsticks a challenge, I still keep a bamboo knife, fork, spoon, (and chopsticks!) set in my backpack when I’m traveling (not only to Japan). It comes in handy.

My background/qualification for this is across ten years, I travelled to Japan three or four times a year for between a couple of weeks, up to two months at a time, in a medium/large industrial town, 200 miles SE of Tokyo. I don’t speak more than a few words of Japanese, learned parrot-fashion. I can also say "I cannot speak Japanese", in Japanese. Whilst there I usually, but not always, was with multiple nationalities which included native Japanese, who managed most of the communication.

Not only will it depend on the restaurant, it is likely to depend on the town you’re in.
I am assuming if you can’t use hashi, you also can’t speak (or read) Japanese.

This can be more of a problem than you might think.

In Tokyo, you can expect to find a reasonable percentage of English speakers, especially amongst the young.
However, culturally, the best English speakers get the best jobs – which doesn’t include waiting tables – so your chances of a waiter/ress speaking English is lower.

Once you get to the smaller towns & cities, this percentage drops off remarkably.

If you can’t manage to communicate by speech [& of course, if you can’t speak it, you haven’t a hope of reading it. Romanji (English alphabet, but not language) transliterations vanish as soon as you leave Tokyo], then very helpfully almost all Japanese menus have pictures. You can point.
This is where the next issue will arrive. They will invariably ask you something at this point. It might be as simple as ‘do you want set?’. This is ‘with all the trimmings’ soup or starter, rice, tea, whatever it is they consider a full meal. If you want set, then just saying ‘setu’ [that U is as short as you can make it, not setooo] will get you the full meal. There’s normally a picture of what constitutes ‘set’ somewhere on the menu too.

…and that’s where communication ends.
No amount of pointing, gesticulating, miming actions or any other type of non-verbal communication will convey that you want a fork. I don’t know why this is, but things you could mime in a German/French/Hungarian/Turkish… restaurant don’t work in Japan.

There was one restaurant I went to every trip for ten years, always on my own because my flight would arrive long before anyone else’s. Every single time I pointed at the same meal, with the same accompaniments, and got it successfully. Every single time they kept asking me question after question that I could only shrug at. To this day I have absolutely no idea what they wanted.

If you cannot point at it, or a picture of it, you cannot order it unless you know the Japanese word for it.
So, if nothing else, find out how to say ‘fork’ in Japanese. Get the pronunciation right* or you will just get confused stares.

Edit – as helpfully pointed out in comments by Jonathan, these days you could always use Google Translate [or similar]. When I was there it was the 90s, we didn’t have such luxury. Even our mobile [dumb] phones wouldn’t work because the networks were different.

*Note on pronunciation. Like any language, Japanese has words that sound similar… but they also have words that have inflections or pitch changes that Westerners simply can’t hear until they’ve had a lot of practise. When most Westerners ask for rice wine, to a Japanese it sounds like they’re asking for salmon. Sake is spelt [transliterated] the same for both, but the inflection is different to the Japanese, if not to the English. One goes up [like a question], the other goes down [like a statement].

If a restaurant does not have fork and knife, you could ask for a pair of training chopsticks. Any restaurant that caters to children should have them. They are connected with a hinge and quite easy to use (basically a pair of tongs).

When I was in Japan it was fork and spoon more than fork and knife but I do not remember even one place to eat where you could not get an alternative for chopsticks.

On the other hand, I had been using chopsticks a few years before going to Japan. And may not have needed the fork.

Depends on the restaurant. Restaurants serving Western-style food will, of course, have knives and forks, and "family restaurants" that cater to children will also have them (but likely in child sizes). There are also quite a few Japanese dishes eaten by spoon, such as the ubiquitous curry rice, or by hand, like sushi, yakitori grilled chicken skewers, onigiri rice balls, etc.

For Japanese restaurants, you can always ask but it will be hit and miss, and you are more likely to find them at a "proper" sit-down restaurant than a tiny noodle stall where patrons use disposable chopsticks.

I would encourage you to try out chopsticks though, you can pick up the basics with only a few minutes of practice (if you can hold a pen, you’re halfway there) and there are many tutorials on the Internet. The disposable wooden chopsticks common in Japan are also the easiest way to learn, since they’re light and many foods like rice stick to them slightly.