hello, here is the detailed difference, hope it is clear.

For soft sleeper, these are private compartments which are fitted out to a higher standard. Each compartment has four bunks and a double action door allowing separate access to the two upper and two lower bunks. Comfortable bedding and good quality pillows are provided. Each bunk is equipped with a small reading lamp. Temperature controls are installed alongside the door. Generally speaking, the facilities include a clothes rack, slippers, clothes brush, stainless steel thermos, fine porcelain teacup and a trash can. Some of the trains may have a squat-style toilet together with a supply of toilet paper. The price is a little higher than the other kinds of seats.

The so-called hard sleeper is generally less comfortable than the soft sleeper. The compartments are open and comprise six fixed bunks, arranged as an upper, middle and lower on either side. Basic bedding such as sheets, pillow slips, blankets and pillows are provided. The space tends to be cramped and inclined to be noisy at times. However, if you are obliged to take an overnight train trip, the hard berth is highly cost effective.