There's this thing that I just don't seem to get.

How do you know, and what is the logic behind when to hook or not when writing a box.

In some cases you have to hook the second stroke and in other cases you don't hook it.

口 kou - no hook
日 ri - hook

Or is this just a case of learning it by heart?

Also when reading signs or texts they don't even show the hook on the characters such as 日, is it important?

Speaking from a japanese perspective, there is no hook in 日

A hook would exist within a character like 子 or 小

Another example would be 小 vs. 忄. I guess the best way to learn it is probably to pay attention to which radical is used where, and learn which radicals are hooked. There may be some exceptions where the radicals have lost hooks.

The way I remember it (from a long time ago), you are technically supposed to put a hook in any box that isn't just a 口. So if a box has something in it, put the hook. Now on Skritter, we make it so you can put the hook or not put the hook on a closed box, up to you.

Certain fonts won't show hooks on those sorts of boxes, but they are lurking there.

Yea I know about characters like 子, 小 or 忄these are absolutely no problem for me, I find it easy to remember when to hook or not with exception of boxes.

Thanks nick, I'm going to check if that is the case, however I do remember there being cases in which there is something in the box and still didn't need to hook, but maybe I'm mistaken.

Thanks for the replies! :)

Hey I just found a character that has a box with something inside that doesn't hook.

错 - cuo4

I really hope there is some logic behind this, but I should know better than to rely on logic when learning Chinese characters :P

Yeah. Well, if it's in 错, it's obviously just a mistake. I wouldn't worry about it.

(Or just an intentional in joke by the Elders of Hanzi).

More seriously, it's probably just as it's considered part of the 昔 element, and not an individual 日 as such. That's guesswork though.

We just built it wrong. I just replaced that stroke in 错 with the non-错 stroke, so that you can properly hook it if you want. If you see others like this, you can hit the "Stroke order correction" feedback tab and George or I can fix them up.