Ushi No Tane - Harvest Moon

As many people know, in harvest moon all letters you recieve in your mailbox are later stored in the bookshelf in your house. I searched for codes(either gameshark or codebreaker) that gave you the full collection of letters but I couldn't find. If you don't know about this it would also help if you have any advice about the supermarket letter telling about the large rucksack(even though i don't buy it, Jeff won't send a letter telling he has one). Thanks

I'm not sure whether or not you are supposed to talk about these coed and what not here, but never mind.

I don't recall getting a letter from Jeff regarding the rucksacks... I think I just went and bought the medium rucksack and then the large one was there straight away... Of course, I may have met some prior requirements which allowed me to purchase both rucksacks in succession to each other... (I think I bought the rucksacks in something like year 2?)

I don't understand why do you want letters for.