In the given code, each letter in the word is substituted by another letter according to a pattern. Let's analyze the pattern from SIKKIM to THUJL:
\[
\text{S} \rightarrow \text{T}, \quad \text{I} \rightarrow \text{H}, \quad \text{K} \rightarrow \text{U}, \quad \text{K} \rightarrow \text{J}, \quad \text{I} \rightarrow \text{L}, \quad \text{M} \rightarrow \text{M}
\]
Now, applying the same pattern to the word TRAINING:
\[
\text{T} \rightarrow \text{S}, \quad \text{R} \rightarrow \text{Q}, \quad \text{A} \rightarrow \text{B}, \quad \text{I} \rightarrow \text{H}, \quad \text{N} \rightarrow \text{O}, \quad \text{I} \rightarrow \text{H}, \quad \text{N} \rightarrow \text{F}
\]
Thus, TRAINING is written as SQBHOHOF.