Once you reach the top of Sokoban, you encounter the zoo. Beyond the zoo are three closets. One of the closets contains the Sokoban prize, either an amulet of reflection or a bag of holding. Take it, for it is the reward for solving Sokoban (or for carefully following the instructions from the Sokoban spoilers).
In brief, each of the three closets contains a prize. You may open the closets and view the prizes: an amulet, a bag, or a cloak. The caveat is this: grab one prize, and the other two disappear. The choice is always between the following:
So how is it done? Which prize do you take, or do you leave the choice for later?
The situation may disturb your strategy. Instead of taking the one prize that was there in vanilla, you may hesitate and leave all three prizes in their closets, to make the decision later. You may fear the Random Number God, and believe that if you take, for example, the amulet of reflection, you will soon find another one sitting in the dungeon.
However, before we proceed, we need to consider the possibility of damage to objects. In NetHack brass, objects (other than artifacts) that provide magic resistance or reflection can wear out from resisting or reflecting one time too many. So, finding a second amulet of reflection would actually be good, because you gain a replacement for if your current amulet disintegrates.
Instead of leaving the three prizes for later, the better strategy is to immediately take the one prize that you want the most and pretend that the other two prizes never existed. This is one of those cases where survival is better than long-term planning.
Choosing the cloak
The cloak of magic resistance is probably the best prize, because magic resistance is so rare and valuable.
You may not want to take the cloak because you think that you will gain magic resistance some other way. Obviously a Wizard who already started with this cloak should not take another one. Also, some roles can gain magic resistance from carrying their Quest artifact around, these are exactly as in vanilla:
- Archeologist: the Orb of Detection
- Caveman: the Sceptre of Might
- Knight: the Magic Mirror of Merlin
- Monk: the Eyes of the Overworld
- Tourist: the Platinum Yendorian Express Card
- Wizard: the Eye of the Aethiopica
These five roles (not the Wizard) should mull whether they think that they can survive without magic resistance until they are able to defeat their Quest nemesis.
After you take the cloak, then in the distant future you may wish for a silver dragon scale mail (instead of a gray dragon scale mail) and gain reflection that way. (That is unless you fear that your cloak will disintegrate and you need a replacement. However, that is a decision for later, not now, not here in Sokoban!)
Choosing the amulet of reflection
Outside of Sokoban, reflection is probably easier to find than magic resistance, because in addition to checking random amulets, you might also encounter a polished silver shield. (Maybe someone should check the exact probabilities to verify or refute this. Maybe YOU should.) The Perseus statue on Medusa's level has the same chance of a cursed polished silver shield as it would in vanilla NetHack.
Avoiding the bag
When choosing the Sokoban prize, avoid taking the bag of holding! (That is unless you already scored both magic resistance and reflection.)
Yes the bag of holding is tempting, because weak characters with less strength often have troubles carrying the weight of their inventory around the dungeon. Without a bag of holding, you will often have to drop items because you cannot carry them all. However at least the cloak of magic resistance or the amulet of reflection offers greater defenses.
Note that you may find a bag of holding in the Gnomish Mines, or Minetown may sell you one. (Know that NetHack brass always fills Minetown with many shops.) Thus you better search for a bag of holding in some other location.
If you cannot locate a bag of holding outside of Sokoban, then save it for a wish. Exactly one bag of holding should last you the entire game, as long as you prevent it (and your stuff inside) from exploding.