Many of the various items have a list of enchantments that would be ideal. For instance, I might want Infinity, Power, Flame, and Punch all on a bow... and at the highest levels. Barring incredible luck, I will never get those with an enchantment table.

I can enchant books until I find those spells, and add them to the bow with an anvil. However, at some point (I haven't yet figured out how many times) it will no longer allow you to add enchantments to an item, saying that it's "too expensive". There is a hidden counter that is incremented every time, and once this goes past a threshold you can never add more magic (though, I've read in places you can continue to repair the item at great cost indefinitely... not clear if that's true or not).

This counter is cumulative, such that if you combine two items' magic into a single item, that won't sidestep the limit.

However, I've only just caught on that one can also combine two books. I can take two Power I books, and make a single Power II book. And I can take two of those, and get it up to Power III, and so on, but also have two spells combined in a book.

If I do this until I get all the magic I need onto a single book (or even just two or three books, supposing the books max out), will I get to the point where the books will no longer combine with the item because it's too expensive? Or are books exempt from the cumulative counter thing? It would suck to spend so much time and effort to get a powerful book and discover that it can't actually be used on anything.

Also, is it true that you can indefinitely repair, as long as you have the repair material and are at level 39? Or is that a misunderstanding of the rules (or maybe just an earlier version of the game and it no longer works like that... I'm on 1.8.9)? Does that only work for those items that can be repaired with diamond/iron, or will it work for fishing rods and bows as well?

2 Answers 2


The mechanic in question here is the so-called Prior Work penalty.

Enchantable items, including books, have a Prior Work penalty stored in their NBT data (RepairCost). The prior work penalty is added to the base level cost of working the item in the anvil.

For a new item, this cost is 0, and it is independent of the enchantments on the item. Each time you do anything with the item in the anvil, such as repair, combine or rename1, the prior work penalty is doubled, and 1 is added. E.g. it is 1 after 1 working, 3 after 2 workings, 7 after 3, or (generally) 2N – 1 after N workings. After 6 workings, the prior work penalty of that item will be 63, making it impossible to work that item any longer outside of creative mode.

When combining two items, both penalties are added to the cost, but the new item's penalty is calculated using only the higher of the two penalties. The optimal strategy is therefore to start high up and combine items with similar prior work penalties.

For example, you want to get a Power V, Infinity I, Flame I, Punch II bow: From enchanting/loot/villager trading, you have a Power IV bow, and Power IV, Infinity I, Flame I and Punch II as separate books. All 5 items have a penalty of 0.

If you just go and put everything on the bow, the bow will have been worked 4 times. Instead, you start by combining the Bow and 1 Book (1 working), and the 3 other books into one (2 workings), then combine those two. You'll end up with only 3 workings this way. You could even combine the bow with yet another book (or bow) before that and still end up with 3 workings on the final bow.

1 Renaming does not apply prior work penalty in 1.9.

  • Thanks for the link. The trivia section is certainly interesting... in 1.8 at least, you can actually overflow these? Is that why they removed "renaming costs 1" from 1.9?
    – John O
    Commented Feb 11, 2016 at 17:03
  • @JohnO I assume renaming increasing prior work was removed to remove the disincentive to name your items, i.e. to remove "Do I name my pick or keep it for one more repair?"
    – MrLemon
    Commented Feb 11, 2016 at 17:26
  • So you get the best results by making sure those penalties are spread evenly over the items you combine? Interesting, thanks! I heard before that the best way would be to 'put as much as possible on books before putting it on items', but that's clearly not true then.
    – Nyerguds
    Commented Apr 30, 2018 at 9:09
  • Is there any way to see the prior work penalty on an item? I have been combining books and throwing them in a chest without realizing this mechanic existed, and it sounds like if I now put this book on an item I could be screwing myself. Would be nice to have a way to see this value! (survival mode on realm by the way, so I don't think I can just cheat). Commented Sep 11, 2020 at 15:31

I don't know the math here but it can sometimes happen that you can put a book with all the enchantments you wanted (´Power V, Infinity I, Flame I, Punch II´) on a bow and sometimes not. This depends on the order of the enchantments on the book.

I beleve that you can get the book you want when you combine 2 books. One with ´Flame I´ and ´Power V´ and the othe with with ´Punch II´ and ´Infinity I´ in the order that they are written

Combine those to get the bow you want. I believe the second book I mentiond before must go in the first slot but I am not shure. Anyway make shure to use a non damaged bow when combining it with the book.

It should cost you 39 levels of xp

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