About orthodoxy

I think sitting upright is a habit and habituation. Recently, many monks, including me, have been living in chairs a lot. Therefore, there are many people who are not good at sitting upright.

As a point, it's best not to move as much as possible when sitting. If you move, your foot will hurt, so don't move. I think the rest is making time to sit up straight every day. Your weight may also have something to do with it.
I'm not an expert so I don't know the details, but these are my impressions.

Hello Kazun-san.

I'm also more comfortable sitting upright than sitting cross-legged. I've gained a bit of weight, but I still usually have an hour to spare.
As you can see when you learn tea, sitting upright also has techniques. The trick is to bring the center of gravity to the center of the foot. If you don't worry about anything, the center of gravity will go towards your legs, so it will put a strain on your knees and it will be easier to get cramps. Pull your body forward by sticking your stomach out. I think there are ways to sit up straight on the internet, so please look it up. Then, after a while, I stood up and sat down again. This alone allows blood to circulate in your legs, and you can continue to sit in a sitting position.

It's a secret story, by the way (laughs). You may think it's amazing that monks often sit all the time, but during the ceremony, they intentionally break their seat by standing, sitting, crouching, and praying quite a bit. So I'm not sitting all the time. That's why mentors don't get numb. On the other hand, being a side monk is harder.
Recently, the number of orthodox seats in temples has increased. My temple also has chair seats. However, I don't sit in a chair. This is because seated sitting every day is a big memorial service practice.
And sitting right is also a form of peace. The samurai sat on their backs so they could stand up quickly and slay them. Rikyubo showed that there was no hostility by attaching a nijiri mouth to the teahouse, taking a sword, and making them sit upright. If you think sitting up straight is an action for peace, don't you think it's a wonderful way to sit? (Laughter) Gassho

In the Jodo sect, orthodoxy is basic, so I usually sit upright, but even so, I only last 2 hours.
So, when you sit still for an even longer period of time, place a seat that is small enough to fit between your legs under your buttocks. It's shaped like a small pillow and feels a little stiff.
If you're cross-legged, it's completely different if you have a seat. You'll also be able to stretch your back. I think people who practice zazen probably use it.
Why don't you try it once?

If you search for seat cushions and zazen futons on the internet, I think it will be a hit.