After 2 nights in the main Nikko area (staying at the spectacular Fufu Nikko), we chose to overnight in Oku-Nikko to tour Kegon Falls and do some hiking in the area. While it was a pleasant stay, Kai Nikko was a massive step down when compared to the fresh, new and luxurious Fufu Nikko.
I've previously leveled criticism at various Hoshino resorts in the past, and most of them apply here - decent but not amazing food, the lack of Onsen (natural mineral hot springs) baths in the rooms, a bit of a corporate feel, slow check-in process and a bit too communal of an experience. As was the case with Kai Tsugaru, Hoshino's Nikko property has definitely seen its better days. The exterior is downright unpleasant - it really, really needs a refurbish in the worst way, beginning with a fresh new paint job. And while there are charming touches in terms of interior decor (numerous nooks and crannies featuring an assortment of ikebana, bonsai, figurines, written scrolls, etc.), there's no getting around the property's age, and it even smalls a bit run down as well.
To start with - for those of you looking for the classic luxury Onsen ryokan experience, I'll get straight to the point - you should look elsewhere. There are no in-room Onsen baths, even in the top suites (only communal ones are available, as well as one rental Onsen that will be hard to reserve given that it's only one), and Kai Nikko offers Samue (looks like spa pajamas) instead of a Yukata. And the Samue are not at all stylish.
We booked the top suite at Kai Nikko - the massive, 170m² lake-view suite (room category "TK6.") It was downright cavernous, but the layout was confusing... tons of small rooms with short hallways that was very disorienting to us. It was definitely not the best use space. If they wanted to cater to the luxury demographic with an uncompromising Suite, they really should have allocated some space for an Onsen bath as well as a dining area (with an option to have meals served in the room.) Basically, it was a decently-appointed room that was super sized, but was not attractive or fresh in a way that would have done the top category room justice.
Given that we're in the COVID-19 era, we prefer not to partake in communal bathing, so the public Onsen baths were not an option to us. Fortunately, Kai Nikko has one private free-flowing, open-air Onsen bath that you can rent. Unfortunately, it's subject to availability and comes at a cost of 3300 yen (roughly $30 USD.) We were fortunate enough to secure a time slot before dinner, but at full capacity I can't imagine too many people successfully booking a slot, given that the times are spread out by 90 minutes (1 hour of use followed by 30 minutes of cleaning by staff.)
The Kaiseki dinner at Kai Nikko was equally underwhelming. While it's "good" (it's very hard to find a bad meal in Japan, mind you), good is not enough in an industry that offers great meals across the board. Nothing was inedible, but several of the dishes were ones that we didn't care to consume the calories to finish. This was in stark contrast to Fufu Nikko, which offered courses after courses (many more so than Kai Nikko, by the way) of exceptionally creative and flavorful courses that were also meticulously explained by the server. Our dinner server at Kai Nikko was charming and worked hard, but she just didn't have quite the command of every ingredient as the lady that served us at Fufu Nikko.
The one thing we do appreciate is the special performances that are on offer at most "Kai" properties. In Nikko, they've devised a "dance" using the famous (but impractical) Nikko-style "Geta" (Japanese wooden clogs) as a way to promote the local artisans that still produce the local Geta. While the dance is in no way traditional or historic in any way, it's performed by members of the staff and it's good entertainment. It's a good way to learn an aspect of the local culture and traditions, and be entertained at the same time.
With a total of 33 rooms, Kai Nikko is a "tweener" in size - larger than most top luxury ryokans, but smaller than a typical hotel. However, at the price point they charge, they should offer services and amenities such as valet parking, more flexible meal time options, a pool/gym and laundry service, which they don't. In other words, it does not offer the benefits of a top ryokan nor does it offer the amenities and services of a luxury hotel (check out the Ritz-Carlton Nikko for an example of the latter.)
I believe that Hoshino Resorts is well aware of the property's shortcomings, however, given that its price point is well below that of competing properties in Nikko. It's perfectly fine if you keep your expectations in check. The problem is, Hoshino markets its brand as if it's the end all, be all of aspirational luxury property stays in Japan, which, from our experience so far, it definitely is not.