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It is acceptable for a woman may hit her abusive husband with a skillet or frying pan with a base thickness equal or less than that of her thumb.

This rule was created in response to the idea that suggests social allowance for a man to hit his wife with a switch of thickness no greater than that of his thumb.
"When he came to, he realized he couldn't be mad as she had not broken the rule of thumb (for women)"
by Fostered Bananas November 13, 2011