4.3 NYSIIS rules.   The NYSIIS code is very much like the Russell Soundex system. Its rules thus produce a name code as well, one using a more complicated set of rewrite rules. These are set out in the following table:

1.	truncate to nine letters1 and code each as its upper-case equivalent
2.	at the beginning of the code change the following sequences of letters
	a.  change MAC to MCC b.  change KN to NN c.  change K to C d.  change PH or PF to FF
3.	at the end of the word change the following sequences of letters:
	a.  change S or Z to null (delete) b.  change EE or IE to Y c.  change DT or RT or RD to D
4.	skip first letter, then proceed letter-by-letter replacing sequences as follows: (if the new sequence results in doubling, do not perform the replacement but delete the letter.2)
	a.  change EV to AF2 b.  change any vowel [A, E, I, O, or U] to A3 c.  change M to N d.  change KN to N e.  change Q or K to C f.  change Z to S g.  change SCH to SSS2 h.  change non-vowel + H to non-vowel i.  change letter + H + non-vowel to letter + non-vowel j.  change vowel + W to vowel
5.	at the end of the word delete S, change AY to Y, and delete A
6.	truncate the code to six letters.

¹It appears that this is not a sound policy, since it may interrupt a consonant sequence that would later be changed by rule if kept intact. However, the rules are written so as to retain the same number of letters when changed, except word finally. Presumably in practice, the final truncation to six letters eliminates garbage in any portions garbled by the first truncation.

²I believe that the “EVAF” would transform to “AFAF”, and not to “AF”. In a similar vein, the “SSS” is not deleted as a resultant double. However, presumably it would be deleted if it followed or preceded an “S”.

³Actually changing “A” to “A” is vacuous.