Choosing seats on the Japanese Shinkansen (bullet train) involves deciding between "Reserved" (Hiteiseki) and "Non-Reserved" (Jiyuseki) cars. If you want a guaranteed seat, especially during peak seasons like Golden Week or New Year, you should book a reserved seat through the JR East/West websites, the SmartEX app, or at a "Midori no Madoguchi" ticket office. For the best views of Mount Fuji when traveling from Tokyo toward Osaka/Kyoto, you must request a seat on the "D" or "E" side (the right side of the train). If you are traveling with oversized luggage (total dimensions over 160cm), you are now required by law to book specific "seats with oversized luggage space" located at the back of certain cars; failure to do so can result in a fine. For a more luxurious experience, you can choose the Green Car (First Class) or the Gran Class (Ultra-Luxury), which offer wider seats, more legroom, and a quieter atmosphere. Most modern stations have multilingual kiosks that allow you to see a map of the car and pick your exact seat location.