How can I publish and protect my board game idea?

if you read section 2(c) of patent act 1977 read as:

It is hereby declared that the following (among other things) are not inventions for the purposes of this Act, that is to say, anything which consists of

(c)a scheme, rule or method for performing a mental act, playing a game or doing business, or a program for a computer;

it can only be protected by copyright i.e. like characters, artistic work, the word used in game etc or design if it involves mechanical or machinery toys.

I recommend you to seek the advice of IP lawyer, so s/he can analyse your proposed game pattern and recommend you possible IPR protection available in your case.

In the United States, board games are covered under the classification CPC A63F. You should consult an IP attorney in order to determine precisely how your board game can in fact be protected by means of a US patent.