Convert from square chain [Gunter, survey] to tatami

Unit Definition (square chain [Gunter, survey])
The square chain [Gunter, survey] is a traditional unit of area in English surveying, defined to be the area of a square whose side equals Gunter's chain (4 rods or 22 yards). Thus the square chain equals 16 square rods, 484 square yards, 4356 square feet, or exactly 0.1 acre.

Unit Definition (tatami)
The tatami is a Japanese unit of area equal to the area of a traditional tatami mat, 0.5 ken by 1 ken or about 90 centimeters by 180 centimeters (roughly 1.62 square meters or 17.5 square feet). This unit, used especially for measuring the area of rooms in houses and apartments, is also called the jo.