How do I get the "Spell" spell in Zelda II?

I've been playing "Zelda II: The Adventure of Link" for the first time. I've arrived at New Kasuto Town and the old man there won't teach me his magic. He just says "Come back when you're ready."

I've been trying to play as unspoiled as possible, but this is cryptic enough that it drove me to consult some online walkthroughs, which are unfortunately unclear and contradictory.

Some walkthroughs say that one needs to have seven magic containers. I assumed this referred to Link's magic level, which for me was six at the time I looked up the info. I went out and did some grinding until I leveled it up to seven, but the old man gave me the same response.

Other walkthroughs claim there are only four magic containers in the whole game, and that they're actually items that boost your magic capacity like the heart containers do for your life. I haven't stumbled across any in my game so far. I could could go out and collect them, but will this get the old man to change his tune? The extra heart containers are useful but not necessary to complete the game, as far as I know, so it seems odd that the magic containers would all be required...especially when they're all so well hidden that I haven't found even one, despite making reasonable efforts to be thorough.

Still other walkthroughs don't even mention the "Come back when you're ready" response, probably because they presume the player has been following along with the walkthrough since the beginning. Not very useful.

Solution 1:

After a bit of searching, I found a similar article about the same issue you were having:

Everytime I go to see the Sage in the hidden town of Kasuto, he says: "Come back when you are ready". But I'm ready! I need that spell to get the magical key and advance in the Hidden Palace.

The solution does require you to grab the 4 Magic Containers in order to gain the Spell from the Old Man.

Western Hyrule

Magic container #1

The first Magic Container is located at the end of a cave southeast of North Castle. No items are required, but the Candle makes it much easier.

Magic container #2

After getting the Hammer, use it on the eastern portion of Spectacle Rock to reveal a cave. The second Magic Container lies at the end.

Eastern Hyrule

Magic container #3

In the middle of a corridor on the southwest part of Maze Island is a hidden grotto. At the end lies the third Magic Container.

Magic container #4

Only after getting the other three Magic Containers can this one be obtained. It is located inside the house of an Old Woman in the Hidden Town of Kasuto.

I will admit though, this does seem odd that no other sources that I have found indicate this.

Solution 2:

You do need all of the magic containers, but this does not refer to your magic level, but rather the size of your magic bar and the number of segments therein, which are expanded by collecting items resembling big potion bottles. Likely, the walkthroughs you have browsed have instructed the player to collect these all along the way, and thus assumes you have them when reaching the point you skipped ahead to.

Try rereading these walkthroughs from the beginning - the first magic container upgrade is found very close to the start of the game and can be acquired in the first few minutes.