Not exactly my concept of "easy".

Anyway, look at box 1. It needs 234789, right?

Well, test each cell for each value, starting with 2.

2) There are a couple of cells that 2 can fit in. Forget it.

3) Same.

4) It can only go in r2c2 (row 2 column 2). It can't go into any other cell because there are already 4's in row 1 and column 1. Great!! Put a 4 there. One cell solved!

789) Not unique. Forget them

Now that we have placed a 4 in column 2 and considering the 4 in column 1, we see that the 4 in column 3 must go into box 4. But 3 and 9 are already there. There is only one place! Put a 4 there. Another cell solved.

But no more progress here

For example with the new 4 in box one on row 2 and the existing 4 on row 1, we conclude a 4 must go into row 3 at box 3. But there are two cells where it would fit. Rats!

But wait! Look at columns 5 and 6. So a 4 must go into r4c4 or r5c4. But there is already a 4 in row 4! Yea! Put a 4 at r5c4!

You are here:

- Code: Select all
`--- --4 --5`

-46 -5- ---

-15 -82 7--

--4 --9 3-6

-73 4-- 89-

1-9 7-- ---

--2 34- 98-

--- -9- 6--

4-- 2-- ---

See if you can see why r4c8=7, r2c9=8, r9c2=9

Fill those in.

Now you can note that as r7c7=9 and r5c8=9 then r3c9=9. Fill in another one!

There may be enough cells filled into row 3 to look for a placement there. Missing is 346.

Look at r3c3. There is a 4 in the column and a 6 in the box. Has to be 3! Fill it in.

What about r3c4? There is a 4 in the box so r3c4 must be 6! Fill it in.

Last missing digit: Put a 4 in r3c8.

One whole row done:

- Code: Select all
`--- --4 --5`

-46 -5- --8

315 682 749

--4 --9 376

-73 4-- 89-

1-9 7-- ---

--2 34- 98-

--- -9- 6--

49- 2-- ---

Well, just keep doing the same thing. It is tough, but you can get there without advanced techniques. Just patience and accuracy.

Mac