Is the minimum contracted length 12 months or can it be shorter?

There are various country programs through Reach to Teach and the contract is different for each one. Their three main programs in Taiwan, Korea and China all require a 12 month commitment. There is however a summer program in Singapore and there may be shorter contracts available in Vietnam.

All public school positions will last a full 12 months. If they are through EPIK, they must be 12 months. It would be pretty rare for a public school to offer anything but a 12 month contract.

Private schools (hagwon) are a little different. While I still think the majority have 12 months contracts, you can find shorter ones. I believe the contracts for hagwons aren't really as binding as they are with public schools, as I see people switch jobs in that sector pretty frequently.

Remember, Reach to Teach is just a recruiter. They will help you find a job in Korea, but your contract is not directly with Reach to Teach. Not every position/contract they find for you will be the same.

The typical contract, at least in South Korea, is 12 months whether it be in a hagwon (private school) or public elementary school. 6 month contracts do exist but I've only ever seen them offered to teachers who have been here a while, like myself. Your first contract through EPIK (the public school recruitment program) is always a year. I've seen no exceptions to that. Hagwons will be the same, they want at least a year guaranteed before you can negotiate.

The length of contract with Reach To Teach, I believe, can vary depending on the contractual length of employment. RTT is a recruiting agency that helps with your placement. I have been in the EPIK program in South Korea for two years now; I was under RTT throughout the first year. The second is solely EPIK.