Otto’s Pizza emloyee Tyler Stratton explains the different varieties of pizza available for purchase by the slice. Slices cost three dollars and feature toppings such as three-cheese tortellini and butternut squash, ricotta, and cranberry.

Otto Pizza, a gourmet specialty pizza restaurant, opened its Harvard Square location on Saturday, filling the empty lot on 1432 Mass. Ave. vacated by Finagle a Bagel in August.

After opening their first location in Portland, Maine in June 2009, founders Michael Keon and Anthony Allen started looking into bringing the pizzeria to Harvard Square about a year ago. The move-in process took the past two and a half months.

Instead of providing a large display board of menu items, the restaurant encourages customers to ask employees about the 24 varieties of pizzas as well as those on display behind the counter.

“We don’t have a menu because we really like to talk to people and explain our pizzas,” said Tyler R. Stratton, general manager of the Harvard Square location. “We see lots of people in the window looking in and wondering what types of pizzas we have.”

The pizzeria highlights their specialty pizzas, which use innovative combinations of toppings, such as butternut squash, ricotta cheese, and cranberries.

“Part of our whole business motto is being simple but doing it correctly,” Stratton said. “We want to be efficient.”

For example, all the prices include taxes and are rounded to the nearest whole dollar. A slice of pizza costs $3, and a 7.5-ounce can of soda costs $1.

Although there are several pizza places open in Harvard Square, including Oggi Gourmet and Pinocchio’s, the workers said they are not intimidated by competition.

“Two blocks is a world away here [in Harvard Square],” Stratton said. “We’re in a great location across from Harvard Yard and between two T stops.”

The restaurant hopes to offer delivery on campus and to local businesses. Stratton added that they are planning a free slice day in the near future.

“We do insane business up in Portland. We’re pretty confident here,” Stratton said. “We’re really going to focus on making this place great.”

Otto Pizza is open Sunday to Thursday from 10:30 a.m. to 1 a.m. and Friday and Saturday from 10:30 a.m. to 2 a.m.

—Staff writer Kerry M. Flynn can be reached at kflynn@college.harvard.edu.    —Staff writer Xi Yu can be reached at xyu@college.harvard.edu.