This is a tough review as the hosts are lovely people however I feel the overall quality of our stay was just unsatisfactory comparative to the cost.
We paid AUD $1,853 for 10 days when we booked 3 months early. The first disappointment was that we discovered the price was increased upon inquiring with the host of availability, and remained higher than the going rate upon checking availability of the dates around our stay one month prior to arriving.
Additional disappointments included being advised the morning of our arrival (so once we had already landed in Japan) that there was construction 'behind' the property which 'may' cause some noise which 'might' disturb our stay. In actuality the construction (which was actually excavation of the land) was next door to the property and right opposite our bedroom wall which is pretty thin and also contains a non closable vent, so we were greeting with the sounds of construction vehicles from 8am every morning. FYI for potential future guests, according to the sign post displayed on the construction site, this construction has been planned since December last year and will continue until end of February 2020. To only be told this the morning of our arrival is extremely disappointing.
Upon entering the property (note it looks like four units within the dwelling are owned by the host, who resides on the third floor), we were immediately greeted by the smell of mould which is present in the kitchen and bathroom area (a glass shower door perpetrates the two). We reported the smell to the host who was quick to apologise and try cleaning it, however despite her best efforts the smell still remained, only to be supplemented by the smell of sewerage coming from what we think was the bathroom drain whenever we turned on the hot water. We tried putting basin plugs in all the drains, but the main bathroom drain doesn't have anything due to the nature of its construction. Depending on your tolerance to bad smells, it's not the end of the world, but it means that you'll essentially need to isolate yourself in the bedroom with all the doors closed, which creates a sense of claustrophobia, which for the price is not acceptable.
Last disappointment was that the TV was faulty and frequently wouldn't turn on. We have no idea why (checked electricity, plugs, everything) and we had to contact the host a couple of times to try to fix it. They were always super apologetic and happy to help (including late at night on one instance), until they fixed the TV by I believe replacing the motherboard inside.
On the good side the apartment is excellently located with two stations within 5-7 minutes walk that provides access to the Yamamoto line (city circle) and Chio line (cuts through the city so you don't have to go all the way around). Location is really fantastic and there was even the best ramen we had in all of Japan located about 7 minutes down the road (Tatsunoya for anyone interested).
Last pros and cons: the host provided both a pocket wifi in addition to separate wifi available in the room which was much appreciated and helpful, umbrellas are provided downstairs to all guests which is nice, the staircase is NOT undercover which will mean the steps will be somewhat steep, narrow and slippery in the rain - keep in mind for mature guests and those carrying heavy luggage, the bed feels like its made from concrete so may not be for those who need soft mattresses, the hosts were otherwise very lovely people besides essentially that they hid the fact of the construction next door (which is extremely souring).
Overall the apartment is what I would consider small and staying with more than a couple would be impossible. The photos give a deceptively large feeling unfortunately, which gets even smaller once you have to close the bedroom door due to the smell from the other side. The internet's fast and great, however the bed is very uncomfortable for those who need softer mattresses. Barring the smell (which I don't know if it could be resolved or not) and the construction noise, the place is lovely, however even then I feel the price is far too excessive, sorry.