This sub was super helpful when I was planning my trip, so I hope I can give back and help other people out with my report. I spent 18 days in Japan earlier this year travelling by myself. My main interests in this trip were gardens, shinto shrines, stationery and all things Ghibli. I had spent 5 days in South Korea before arriving in Japan, so take that into account. I apologize in advance for the formatting, I'm not very familiar with the web version of Reddit. I'll try to go into more detail for the places that haven't been extensively covered here and just touch on the more popular attractions.

PREPARATIONS

Reservations

I reserved pretty much all attractions in advance. The most competitive were for sure Ghibli Park, Ghibli Museum and Kirby Café. Others like the Takachiho boats and Kabuki one-act tickets were competitive but there was about an hour margin to get what you wanted. The rest was pretty easy.

Learning Japanese

I started learning basic Japanese with Duolingo a year and a half before my trip. This ensured I had a grasp on the basics and I ended up being able to handle a lot of recurring situations fully in Japanese, which I was proud of. I didn't even try to learn kanji, though, and my katakana and hiragana were only passable, but speaking and understanding is much more important anyway. I took five private lessons on the weeks before the trip to perfect pronounciation and practice real-life situations and these helped a bunch as well.

Medicine

I was staying for less than 30 days so technically I didn't have to worry about this, but just in case I had my prescriptions and a letter from my doctor translated to English so I could present it at the airport if I needed to. Turns out no one cared, noticed or asked, so I didn't have to use them, but I still suggest doing this if you're bringing any kind of controlled medication into Japan, just in case.

ITINERARY

Day 1 – Fukuoka (airport) and Kumamoto

• I had an 8 o'clock flight from Seoul to Fukuoka, which looking back was a horrible decision. I was anxious about missing my flight so I got to Incheon the night before and had to sleep on a very uncomfortable bench because the airport capsule hotel was fully booked and there were no immigration services at night. Obviously, I got to Fukuoka feeling very tired.
• Had an e-sim from Airalo and it took a bit longer to activate than in South Korea but still worked fine.
• Immigration was very easy in Japan. I had my QR code ready and that was basically it.
• Sent my larger luggage to Osaka at the Yamato counter. Spent the next few days with only a carry-on.
• The airport itself has a free bus to the train station, which was helpful. Bought my tickets at the machine but then learned I had to get a base fare ticket as well, so had to turn around and go back and almost missed my train. So after this I was determined to not get any reserved seating tickets and only get my tickets at the booth with an attendant.
• Got my Sugoca at the Kumamoto train station and continued to use this card for the rest of my trip. Accidentally added too much money to the card because I was still thinking in Korean Won so I decided to only have dinner at convenience stores.
• My brain still hadn't fully shifted from Korean to Japanese and I was very tired so I ate at the only restaurant with an English menu at the station.
• Bought train tickets for the following day at the counter. This became my routine: every time I arrived at a new city, I would buy the train tickets for the next leg of the trip. Highly recommend this to everyone, as it allows you to take your time finding your gate and platform.
• Went to my hotel (Super Hotel Kumamoto Ekimae) to wait for check-in time. I think this is the hotel I liked the most during my trip even though I only stayed for one night. Wish I had booked this chain for other cities as well.
• Took a short nap instead of immediately heading out to see the sights because I was wiped.
• Took the tram to Kumamoto Castle to see the sunset from up there. Sadly the castle itself had closed at 4pm but it was still beautiful to see from the outside and the restoration work is very insteresting. Had a lovely walk around the castle and back to the tram.
• My original plan was to also visit Suizenji Jojuen and Kumamon Square but it got dark earlier than I expected and there were already a lot of Kumamon stuff at the train station itself so I just took the tram back to the station. I honestly loved riding the trams, they're very charming. It's a slower way to get around but you really get to see the city and peoplewatch.
• Bought dinner and snacks for the next day and went to sleep.
• STEP TOTAL: 12,818

Day 2 – Takachiho

• I had booked a tour of Takachiho and the Aso caldera in advance with Explore Kumamoto because I can't drive. This was probably my favourite day of the entire trip. The guide (Helen) was lovely and told us so much about the area, and the other people on the tour were great as well.
• We got to Takachiho gorge early in the morning and I already had a reservation for the canoes as suggested by our guide. This was very helpful because otherwise we would've had a 3 hour wait and obviously wouldn't have made it. The gorge itself is smaller than I expected but the whole place is so beautiful, I still think it's very much worth the visit.
• After walking around and rowing, we had lunch on-site and had Nagashi Somen (cold flowing noodles). I did better than expected at this and had so much fun. The locals thought we were funny celebrating our abilties with the chopsticks and that was also fun. Also had nanban chicken and man, that was delicious.
• Visited several spots in the caldera for the rest of the day, can't recall all the names. Unfortunately Mt Aso was spewing some gas so we couldn't go up all the way but it wasn't my main interest so I didn't mind. Just driving around was already so lovely, I really can't stress enough how much I loved this day and would recommend this stop for everyone.
• Got a train to Oita from Kumamoto. Arrived pretty late, bought train tickets for the next few days, had a konbini dinner and that was it. Stayed at Toyoko Inn Oita Ekimae. Pretty standard business hotel, very good breakfast. Got a surprisingly large room.
• STEP TOTAL: 14,182

Day 3 – Yufuin

• Boy do I regret this one. I had planned to spend the day at Yufuin but it was so small. If I had known I would've either skipped this entirely or done half a day here and half a day somewhere else (maybe Beppu).
• The Floral Village is literally just two blocks of character-themed shops, lake Kinrin is very small, and you can cross the whole town in like an hour. Thought about spending time at an onsen but I have tattoos and didn't want to go around asking and getting rejected. It's not even a relaxing place because there are constant busses dropping people off all day so it's way too crowded for how small it is.
• Good food options, though. Had dessert at Snoopy Chaya and ate anpan at Miffy Kitchen, had some kind of japanese version of bao for lunch.
• Went back to Oita and basically had my first slow evening of the trip.
• STEP TOTAL: 9,298

Day 4 – Osaka

• The train trip to Osaka was the longest of the whole trip. Left at 8 a.m., got there around midday. Bought tickets for the end of the week but messed up with my Japanese and apparently instead of buying tickets for 4 p.m. I bought tickets for 4 people. I'll get into this later.
• Dropped off my luggage at APA Hotel Namba-Shinsaibashi. I didn't know about the owner's horrible politics when I booked hotels for this trip so ended up staying at an APA twice. Both times I got to one address and had trouble checking in until they figured out I was actually staying at another branch two blocks away from where I thought I was staying. So if you're staying at an APA do plan some time around the check-in in case this also happens to you.
• Went to Okonomiyaki Ajinoya for lunch. This was the only place in the whole trip where I had to wait in line. I wouldn't classify this as a tourist trap because the food was very good and portions were large, but be mindful of the wait.
• Headed to Osaka Aquarium. Loved doing the stamp rally. All the animals looked healthy and active, which was a concern I had after finding out how bad animal conditions can be in Japan.
• Originally I had planned to go to Shinsekai but it was late so I instead walked around Dotonbori, took lots of pictures, ate some street food, had a good time.
• STEP TOTAL: 14,198

Day 5 – Osaka Universal Studios

• I'd heard about the gates opening an hour earlier than they say and it was true! I only had a standard ticket so I run-walked to Super Nintendo World and got in with no need for a timed entry ticket.
• Rode Mario Kart in basically 15 minutes. I won't go into details for this day because I think it's been sufficiently covered online, just wanted to add that the mushroom cream popcorn is delicious.
• The Harry Potter area was a letdown. I'm not the biggest fan so I just wanted to go on the rides. Ended up wasting almost 2 hours in line for the rollercoaster before I got a good look at how small it was and gave up.
• The Jurassic Park area was all closed, unfortunately.
• Did some laundry at the end of the day
• STEP TOTAL: 13,862

Day 6 – Osaka

• Started the day at the Museum of Oriental Ceramics. Highly recommend this museum. Most of the ceramics are from South Korea, but the collection is amazing.
• After this I went to LUCUA and the other shopping center nearby, did a lot of character and stationery shopping.
• Then headed to Umeda Sky. Unfortunately it was cloudy but I had booked my ticket in advance so oh well.
• At this point of my trip my back and feet were killing me. I had to actively push myself to go out on the evenings. Asked for help on the subreddit and they recommended some kind of stickers for tired feet and that worked very well. Unfortunately I don't remember the brand name.
• Spent the evening at Shinsekai eating a bunch and taking pictures.
• STEP TOTAL: 19,281

Day 7 – Osaka and Kyoto

• Skipped Americamura because I wasn't in the mood to shop, went to Shinsaibashi PARCO only because I still needed to buy a few gifts for friends.
• Went to Namba Yasaka Shrine. Very cool.
• Had lunch at Kushiya Monogatari. By the time I figured out the right level of batter and frying time I was full, so I didn't make the most of the buffet, but it was a fun experience. Don't think it's worth the hype though.
• Collected my luggage and headed to Osaka Station. Had an awful go this time, first because I found out that the Yamato unit was outside the station so I had to go all the way there and back, then found out about the 4 tickets situation and had to find the desk where I had originally bought the tickets to get a refund and then re-purchase a single ticket. I did think it was weird that they gave me so many stubs originally but I hadn't ridden the shinkansen yet so I assumed it had something to do with that. Fortunately I made it just in time to catch the train, which was so fast I almost missed my stop because I thought there was no way we had left Osaka already.
• Arriving in Kyoto, I bought my tickets for the end of the week and made extra sure to check the ticket information this time.
• Checked in at The Millenials Hostel. The bed was comfortable, the bathrooms were great and they had very decent storage space, so I was satisfied.
• Don't think I did anything else this day, just walked around where I was staying.
• STEP TOTAL: 15,149

Day 8 – Kyoto

• Got to Katsura Imperial Villa for a guided tour, but then found out that I had messed up and gotten a ticket for the day previous and had to buy another ticket, which was fine, but made me lose an hour. This was one of my favourite places to visit in the whole trip. The tour was bilingual and very interesting, the garden is beautiful. It's a bit outside of the main city but it's worth it.
• Headed to Nijo-jo, which I also enjoyed.
• Walked to the Face House, had lunch on the way. Unfortunately the shop at the Face House was closed but it was still cool to see it, and I really liked walking around a more residential area.
• Next up was Kyoto Botanical Gardens. I had such a lovely afternoon there. At this point it was late May and most flowers weren't blooming anymore, but the pavillion still had flowers and the roses were in full bloom. Also one of my favourite places in the trip.
• Took a very long walk to the Turtle Stepping Stones. It was much further away than I had anticipated but walking by the river was very pleasant and the weather was nice. Sat down and rested near the stepping stones and peoplewatched until the sun started to set, then headed back to the hostel.
• STEP TOTAL: 22,324

Day 9 – Kyoto

• Woke up at 4:30 and grabbed the first train to Fushimi Inari. It was raining lightly so there was almost no one there. Did the whole climb in two hours, then waited for the temple at the base to open. One big downside of climbing it so early is that none of the rest stops were open. Thankfully I'd brought enough water and snacks. I did get some beautiful pictures, though.
• Went back to the hostel and napped until lunch.
• After lunch, I headed up to Otagi Nenbutsu-ji. It was small but quite nice.
• Okochi Sanso was next. I thought the trail was very narrow and slippery so it was kind of a stressful experience. Wouldn't recommend this, personally.
• Walked through the bamboo forest mostly because it was free and on my path
• Walked around Arashiyama, bought some gifts for my friends
• Headed back with a brief stop at the Pokémon Center
• STEP TOTAL: 25,694

Day 10 – Kyoto

• It had continued to rain all night and the rain was much heavier now. Went to Nanzen-ji, then headed to the Kyoto Costume Museum, which was lovely. Unfortunately it seems that they are under renovation so I only saw a reduced version of the collection, but it was still cool.
• At this point it was raining so much that the streets were starting to flood and my shoes were soaked through. Headed back to the hostel and had lunch at Motoi Gyoza. Their house sauce is delicious, I definitely recommend stopping by!
• The plan was to go to Gion and Pontocho Alley but the rain did not let up. Ended up going to Nishiki Market instead, as well as UniQlo to buy more socks and the MoMa Design Store.
• STEP TOTAL: 12,232

Day 11 – Kyoto and Nagoya

• Originally the plan was to go to Kinkaku-ji in the morning and then spend the day in Shigaraki before heading to Nagoya at night, but I didn't want to leave not having seen Gion, so I ended up not going to Shigaraki after all, which is a bummer.
• I did go to Kinkaku-ji though, then walked through Yokai Street, which was severely underwhelming. Only saw like 3 ratty yokai statues in total and the shops weren't interesting. Definitely skip this.
• Headed to Gion. Got lost. Didn't know how to find the pagoda so I asked tour guides in the area until I found it. Honestly, I could've just gone to Shigaraki instead. It seems like Gion would be way cooler at night, but during the day it was just okay.
• Took the train to Nagoya. Got there decently early, checked into the second APA Hotel. I wanted to use the hotel onsen but they don't allow tattoos, so bummer. I had so much back pain at this point, so I looked up massage places nearby and found one that I was sure did not involve happy endings. I had never had shiatsu before and it was tough but I felt like a brand new person at the end.
• STEP TOTAL: 17,325

Day 12 – Ghibli Park

• I honestly only came to Nagoya for this and it was so worth it.
• Not much to say because it's been covered extensively already, but I can answer questions if anyone has them.
• STEP TOTAL: 14,787

Day 13 – Tokyo

• Last train of the trip! For the first night I was staying at the Shinjuku Book and Bed, which I had known about for years and was really excited about. I still only had my carry-on at this point but I was carrying a large shopping back and my backpack as well because I uh… underestimated how much I would buy.
• Dropped my luggage off and headed to the Tokyo Ad Museum, which was very cool and I definitely recommend a visit! Their exhibition is super interesting. I wanted to stick around because the NT Tower clock was nearby but it was very windy and cold and I gave up before the tow.
• Headed to Ginza and spent so much time (and money) at Ito-ya. Walked around Ginza and went to Tokyo Station and Character Street, then headed back to the hostel, dropped off my purchases and had dinner at Ghifu-ya.
• Spent a quiet night at the hostel reading a book of Japanese short stories and enjoying the ambiance.
• Didn't sleep super well because the hostel is very noisy (which I'd heard about, hence me only staying one night)
• STEP TOTAL: 15,009

Day 14 – Tokyo

• Had a quiet breakfast and read some more, then gathered up my stuff and moved hotels to Toyoko Inn Tokyo Uguisudani Ekimae. This location turned out to be perfect. It's on the Yamanote Line but very quiet and residential, I really enjoyed staying here. (Also, good breakfast!) The room was MUCH smaller this time and even though I knew that was a risk with business hotels, this one was even tough to walk around. Made packing much harder.
• Went to the Tokyo National Museum, loved it. Had lunch there as well, which was a bit pricey but tasty.
• There was some kind of event going on at Ueno, so I walked around and watched a local JPop group performing. The plan was to also do Sogenji and Senso-ji on this day but like I said I had not slept well and instead headed back to the hotel for a nap.
• Later I went to Shinjuku to go to Sekaido. At this point I was shocked at how much I had spent on this trip so I started cutting back on a few things. Went to Dagashi Bar but didn't stay because I didn't feel like drinking by myself, headed instead to Goldfinger, which is a lesbian bar close to 2-Chome. They don't do karaoke anymore sadly but I still had a great time and made some friends!
• STEP TOTAL: 18,686

Day 15 – Tokyo

• Woke up later and went to Gotokuji. I had been told this was a tourist trap but honestly I loved it and I do think it's worth the time to go.
• Went to Harajuku and had lunch at the Pompompurin Café. They give you a Purin seatmate if you're there by yourself, it's very cute.
• Walked around Harajuku, bought more gifts. It started raining more heavily so I threw myself into the first Starbucks I found and wouldn't you know it, it was the Shibuya Crossing Starbucks. I found the crossing extremely underwhelming. The one near Shinjuku Station is much larger so I didn't get the hype. Decided it wasn't worth it to wait for sundown over there, said hi to Hachiko and went back to the hotel to rest. Really didn't do much at night these last few days because I was so tired.
• STEP TOTAL: 12,393

Day 16 – Tokyo

• Slept right through an earthquake. The alarm on my phone didn't make any noise at all.
• Started my day at the Ghibli Museum, which was amazing.
• Then I headed to this tea shop that I really wanted to check out, it's called Shorakuen. Their specialty are these tiny cakes shaped like Mt Fuji and other Japanese mountains. Everything there was beautiful and delicious, I really recommend it. A bit pricy but really on par with the service and the food.
• It was raining again so I skipped Yoyogi Park and just went to the Skytree because I already had tickets. Watched the sunset from there and hung around at night until the tower was completely engulfed by clouds. I'm really happy I got to see the view despite the rain, that was very lucky.
• Asked at my hotel about their same-day luggage delivery service to the airport and decided it was worth it. Had a really hard time packing my bags in my tiny room.
• STEP TOTAL: 13,594

Day 17 – Tokyo

• I had originally planned to go to Akihabara in the morning but decided instead to go to Senso-ji and Sogen-ji because I had missed out earlier. I thought this was a good decision, it saved me some money for sure. Had some conveyor belt sushi and loved everything.
• I had a backup plan to go to Sunshine City but ended up not needing it, both because at this point I had already bought everything I wanted and because I got single-act Kabuki tickets!
• Spent some time at Bunmeido and at the gallery under the theater before the play started, then went up. Unfortunately the month's plays were focused on more grounded, real-life stories so I didn't get to see fancy makeup and costumes, but I still really enjoyed the experience. Wish I had also gotten a ticket to see the dance act.
• STEP TOTAL: 11,211

Day 18 – Last day in Tokyo

• Woke up early to leave my bags with the transport service and headed to the Imperial Palace. The guided tour wasn't that great, you can't see basically any older structures, so I would say this would be a skip for me had I known.
• Wanted to go to Tobichi but I didn't realise they closed on a weekday. Got really sad about this.
• Went back to the SkyTree for my Kirby Café reservation. The food was underwhelming but very pretty.
• Headed to Asakusa Pier to get on the Tokyo Cruise. I booked this because I wanted to see all the different bridges but the structure of the boat was so that you couldn't really see up, only sideways, so that ended up being a waste of time. Got off earlier than I had planned out of sheer frustration.
• Headed to the airport and got one last melon soda.
• STEP TOTAL: 16,574

INSIGHTS

First of all, everything in Japan was smaller than I expected. I wish I had known this simply to adjust my expectations.

On the months prior to this trip, I focused my workouts on walking long distances and climbing stairs but I ended up neglecting my back and shoulders, which left me with a lot of pain during the trip.

I had brought a tripod with me but this was a waste of space, as it was a pain to carry around and I never used it. It was easier to just ask other tourists to take my picture.

It was very easy to pay with credit card pretty much everywhere. I had a VISA and a MasterCard and both were accepted pretty much everywhere.

Coin purses are a must. I can't emphasize enough how much you need one. Tiny hand towels as well.

USEFUL PHRASES

(Besides the usual, of course)

(Watashi no) sashin o totte kuremasuka? – Can you take my picture?

XYZ wa nangai desu ka? – On what floor is XYZ?

Eki stampu ga arimasuka? – Do you have an eki stamp?

Dono hoomu? – Which platform? (when you show a station worker your ticket)

That's all! I'm happy to answer any questions. Hopefully this helps someone else.