What can you tell me about Japanese "snack" bars?

"Snack" - or sometimes called pubs, or pub snacks,- are small, Japanese style bars. They can be found in any neighborhood in Tokyo or any other town in Japan.
They can be intimidating to enter for the first time as they usually have no windows and no outdoor menus or signs that give you an idea of what is inside. Interior usually consist of only bar seating and few or no tables. Most often behind the bar will be the Mama-san proprietress.
Customers are usually regulars from the neighborhood and mostly male. Table charges (usually 500yen~) are the norm as is buying your own bottle of shochu (3,000yen~) to be drunk mixed with water or tea. If you don't finish the bottle, the Mama-san will write your name on in and put it behind the bar, ready for your next visit. Service usually includes a karaoke machine (no booths, singers sit at their bar stool and sing for the entire crowd) and a pretty, young girl who'll converse with each customer. Higher class joints in Ginza or Akasaka will have
For a foreigner in Japan, your best bet for going to a nice snack would be to have someone invite you and take you to his favorite haunt.