They are hostess bars. You pay something like 4,000 yen/hr to drink watered down shochu and talk to the ladies. You can arrange a dohan, you go on an early date and then go back to the bar with her - I don't know what that costs.
In theory you could strike up a personal relationship with a lady over time but you are more likely to be seen as an ATM, they have many techniques to extract money from their customers.