A Japanese toilet works near the same way as an American Toilet unless the Japanese toilet is a squatting toilet.
With Japanese squatting toilet the person squats down and poops or pees and then water flushes down the poop or pee.
The flush of a Japanese squatting toilet is often operated in the same manner as a Western toilet, though some have pull handles or pedals instead.
Many Japanese toilets have two kinds of flush: "small" (小) and "large" (大).
The difference is in the amount of water used.
A Japanese toilet is most often a toilet that sits down into the floor where you squat down to pee or poop.
Some Japanese toilets are like regular toilets and some have heated seats, sensors to dry your bottom, automatic open lids etc.
The reason public toilet seats are open in the front is to make it easier for people to clean up after themselves.
With the open toilet seat at the front you can reach under and through the toilet seat to wipe your butt.
The open toilet seat also allows women to wipe their vagina or perineal area without contacting the toilet seat.
You should shut the toilet lid when flushing the toilet as flushing the toilet sends bacteria into the air.
When you just pee it's not always necessary to flush the toilet with the lid closed as not as many germs will float around.
But with poop germs can float around but it's not really a problem if you do flush the toilet without closing the lid.
You should flush the toilet every time you pee, especially if you live with other people.
If you live alone then it's not always necessary to flush the toilet just when you pee and you can wait until after a few more pees or wait until you poop to flush the toilet.
However for me I always flush the toilet when I pee as I just don't like leaving anything in the toilet.
I was always disgusted when I lived at home with my parents and they would leave the pee in the toilet.
I would always flush it regardless as the pee eventually started to stink.
Pee is pretty sterile but as it sits out in the air after it leaves your body the pee starts turning to ammonia and can begin stinking.
If you live with others then it's best to flush the pee down the toilet.
Flushing a toilet uses at most 1 gallon or slightly over 1 gallon of water per flush.
If you need to conserve water then yes you should avoid flushing the toilet every time you pee but otherwise you should go ahead and flush the toilet.
My water bill has a minimum use of 2,000 gallons anyway so even if I don't use the 2,000 gallons of water a month then I still pay for it.