I Looked Into Matsuzakaya Honten at Hakone Ashinoyu Onsen

This blog has mainly focused on campgrounds and day-use hot springs, but every now and then I sneak in a post about accommodations too, for those days when I'm thinking more about a "hocance" (hotel-as-vacation) mood rather than camping.

This time, I looked into Matsuzakaya Honten, located in Hakone's Ashinoyu Onsen area. I came across information saying that a single hot spring source apparently produces three different spring qualities—sulfur, sulfate, and bicarbonate types—and that got me curious enough to dig in.

What Kind of Ryokan Is Matsuzakaya Honten?

This is a ryokan located in the Ashinoyu area of Hakone, in the Ashigarashimo District of Kanagawa Prefecture. It was apparently founded in 1662. It seems to be a place with quite a long history—according to the official website, a meeting between Kido Takayoshi and Saigo Takamori took place here during the Meiji era, and the names Katsu Kaishu, Yamaoka Tesshu, and Soejima Taneomi are also mentioned as former guests. Members of the imperial family are said to have visited as well, and one of the guest room buildings, called HANARE, is introduced as a former imperial villa.

Check-in is from 3:00 PM and check-out is by 11:00 AM, apparently. Reservations can be made through the official website or by phone, and it also seems to be available through major booking sites. From Hakone-Yumoto Station, it's about a 25-minute ride by Hakone Tozan Bus, or about 20 minutes by car from the Susukigawa interchange on the Hakone Shindo. There's parking for 22 cars, free of charge and with no reservation needed, so it seemed relatively convenient for those arriving by car as well.

Komorin

Hearing that it was founded in 1662 is already enough to make my head spin a little, but even someone like me who isn't great with history had to go "whoa" at the idea that it was the site of the meeting between Kido Takayoshi and Saigo Takamori.

The Private Hot Spring Source "Ashikari no Yu," Said to Have Three Spring Qualities

The most notable feature of this ryokan, and something I found genuinely interesting while researching it, is the private hot spring source called Ashikari no Yu. The spring quality has quite a long name—sulfur-calcium-sodium-magnesium sulfate-bicarbonate spring (hydrogen sulfide type)—and it's apparently classified as weakly alkaline, hypotonic, and high-temperature. Having three components—sulfur, sulfate, and bicarbonate—combined in a single spring source seems to be quite a rare type of hot spring.

• Source temperature: 58.6°C, with the bath temperature adjusted to around 41.0°C
• pH 8.1, with an output of roughly 300,000 liters per day (about 200–250 liters per minute)
• Apparently 100% flow-through, with no added heat, no added water, and no recirculation
• Depending on the weather and temperature, the water reportedly can change from an emerald green color right after emerging to a cloudy white color

There's one large communal bath each for men and women, and both were apparently renovated in 2023. Bathing hours seem to be split into two periods: from check-in until midnight, and again from 5:00 AM to 9:30 AM the next morning. There's also a lounge area for after bathing where you can apparently look out over a Japanese garden.

On top of that, there are apparently 5 private outdoor bath rooms available, which you reserve at the front desk after checking in (advance reservations aren't accepted). The regular price seems to be 5,500 yen (tax included) per room, though at the time I checked for this article, there was information suggesting stays through September 30, 2026 might be free. That said, pricing conditions like this can change, so it's probably worth checking the official website for the latest information before booking. There also seems to be a day-use plan where you can use a private outdoor bath room with its own source for 17,600 yen (for 1–2 people, including drinks and bath towels), which could be a nice option for anyone who wants to drop by without bringing much.

Guest Rooms and Facilities, Checked from an Indoor-Lover's Perspective

There are 21 guest rooms in total, spread across 5 buildings, and the grounds cover roughly 4,000 tsubo (about 13,200 square meters), which is quite spacious. The buildings seem to have quite different atmospheres from one another—HANARE, the former imperial villa; Shunpuso, said to be a relocated building from the Taisho era; Ashikariso, designed for two guests; and Kakumeikan, built in the Meiji era. Most rooms apparently come with an indoor bath and an outdoor bath, but Kakumeikan is described as having only a shower, so it might be worth checking whether a room has a bath before choosing it.

Rooms come with the usual set of amenities—refrigerator, TV, individual air conditioning, free Wi-Fi, and so on—and the toiletries apparently include body soap and shampoo from the Sensatia brand. Free-of-charge rental items like humidifiers, irons, and low-resilience pillows are also available in limited quantities, which struck me as a quietly appreciated point for someone like me who tends to stay indoors.

There's a Meiji-era Western-style lounge inside the building, and I saw mentions that drinks, including alcoholic ones, could be enjoyed there for free, though there was also information suggesting this might become a paid service starting October 2026. Conditions like this may have changed depending on when you're reading this, so it's worth checking before booking. The bar lounge is currently closed for business and seems to be usable as a reading space with a view of the inner courtyard. The sunken-hearth room apparently has toys for children too, like shogi and playing cards.

Dinner is served under the name "Shukuba Kaiseki," a multi-course meal whose menu apparently changes according to the eight seasonal divisions of the twenty-four solar terms. Breakfast goes by the name "Traveler's Breakfast," said to recreate old post-town cuisine using modern ingredients. Meals appear to be served at the dining hall called "En," and I couldn't confirm from the official website whether in-room dining is available. Vegan and vegetarian accommodations seem to require advance notice of 3 days, though there was also a note saying full gluten-free support isn't possible.

Komorin

Hearing that free humidifier rentals are available is reassuring enough on its own for someone like me who really doesn't do well with dry air. I'd like to think fellow indoor types understand not wanting to lose to dryness even while traveling.

Rakuten Mobile Signal Conditions

Using the official "my Area Communication Simulation" tool, I entered the location of this facility (the Ashinoyu area of Hakone) and checked the signal, and the overall rating came back as C.

Ashinoyu is located in a mountainous part of Hakone, so this result didn't seem out of place given the terrain. If you're planning to watch a lot of videos during your stay, or need to stay on top of work messages, it might be reassuring to think through some countermeasures ahead of time based on this rating.

Komorin

Honestly, seeing a C rating made me brace myself a little. But then again, maybe when staying at a hot spring ryokan, putting your phone aside and just relaxing is a perfectly valid option too.

Wrapping Up

To sum it up again, Matsuzakaya Honten struck me as a ryokan where you can enjoy a rare flow-through hot spring, with a single private source producing three types of spring qualities—sulfur, sulfate, and bicarbonate. Between its history dating back to 1662 and the variety of guest rooms, including HANARE, the former imperial villa, it feels like a place well suited for anyone who wants to fully savor the hot spring experience itself.

On the other hand, the Rakuten Mobile signal came back with a C rating, so if connectivity matters to you, it's probably a good idea to check for yourself beforehand. Some details, like pricing, complimentary lounge drinks, and the free private outdoor bath campaign, seem to be subject to change, so when you actually book, it's probably best to check the official website for the latest information first.

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Related Links

• Official Site